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LIBRARY 

THE  UNIVERSITY 
OF  CALIFORNIA 

SANTA  BARBARA 


PRESENTED  BY 

Wi 1  bur  R,  Jacobs 
UCSB 


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THE 


USEFUL    ARTS, 


CONSroERED  IN  CONNEXION 


APPLICATIONS   OF  SCIENCE 


WITH  NUMEROUS  ENGRAVINGS. 


BY    JACOB    BIGELOW,    M.D. 

PROFESSOR  OF  MATERIA  MEDICA  IN  HARVARD  UNIVERSITY,  AUTHOR  OF 
'  THE  ELEMENTS  OF  TECHNOLOGY,'  ETC.  ETC. 


IN  TWO  VOLUMES. 

VOL.  n 


N  E  W    Y  O  R  K  : 

HARPER   &   BROTHERS,  PUBLISHERS, 

329   &  331    PEARL   STREET, 

FRANKLIN    SQUARE. 

1863. 


Entered  according  to  Act  of  ('ongress,  in  the  year  1840,  by 

Marsh,  Capkn,  Lyon,  and  Webb, 
in  the  Clerk's  Office  of  the  District  Court  of  Massachusetts. 


CONTENTS 


CUAPTER  XIV. 


ARTS  OF  LOCOMOTION. 


Motion  of  Animals  ;  Inertia  ;  Aids  to  Locomotion 
Wheel  Carriages  : — Wheels  ;  Rollers  ;  Size  of 
Wheels  ;  Line  of  Traction  ;  Broad  Wheels  ;  Form 
of  Wheels  ;  Axletrees  ;  Springs  ;  Attaching  of 
Horses.  Highways: — Roads;  Pavements;  Wood- 
en Pavements;  McAdam  Roads.  Bridges:  — 
Wooden  Bridges  ;  Stone  Bridges  ;  Cast-Iron 
Bridges  ;  Suspension  Bridges  ;  Floating  Bridges. 
Rail  Roads  : — Edge  Rail-way  ;  Tram  Road  ;  Single 
Rail  ;  Passings,  or  Sidings  ;  Turn  Plate  ;  Curves  ; 
Propelling  Power  ;  Locomotive  Engines  ;  Station- 
ary Engines.  Canals  : — Embankments  ;  Aque- 
ducts ;  Tunnels  ;  Gates  and  Weirs  ;  Locks ; 
Boats  ;  Size  of  Canals.  Sailing  : — Form  of  a  Ship; 
Keel  and  Rudder  ;  Effect  of  the  Wind  ;  Stability 
of  a  Ship  ;  Steam  Boats  ;  Steam  Ships.  Diving 
Bell : — Submarine  Navigation.  Aerostation  : — Bal- 
oon  ;  Parachute, 9 


CONTENTS. 


CHAPTER  XV, 

ELEMENTS  01    MACHINERY. 

Machines  ;  Motion.     Rotary,  or  Circular  Motion  :— - 

Band  Wheels  ;  Rag  Wheels  ;  Toothed  Wheels  ; 
Spiral  Gear  ;  Bevel  Gear  ;  Crown  Wheels  ;  Uni- 
versal Joint ;  Perpetual  Screw  ;  Brush  Wheels  ; 
Ratchet  Wheel  ;  Distant  Rotary  Motion  ;  Change 
of  Velocity  ;  Fusee.  Alternate,  or  Reciprocating 
Motion  : — Cams  ;  Crank  ;  Parallel  Motion  ;  Sun 
andPlanet  Wheel  ;  Inclined  Wheel  ;  Epicycloidal 
Wheel  ;  Rack  and  Segment  ;  Rack  and  Pinion  ; 
Belt  and  Segment  ;  Scapements.  Continued  Rec- 
tilinear Motion  : — Band  ;  Rack  ;  ^Universal  Lever  ; 
Screw  ;  Change  of  Direction  ;  Toggle  Joint.  Of 
Engaging  and  Disengaging  Machinery.  Of  Equal- 
izing Motion  : — Governor  ;  Fly  Wheel.  Friction. 
Remarks,         .  .     5^ 

CHAPTER  XVI. 

OF  THE  MOVING  FORCES  USED  IN  THE  AR1&. 

Sources  of  Power  ;  Vehicles  of  Power,  Animal  Pow- 
er : — Men  ;  Horses.  Water  Power  : — Overshot 
Wheel  ;  Chain  Wheel  ;  Undershot  Wheel  ;  Back 
Water  ;  Besant's  Wheel  ;  Lambert's  Wheel  ; 
Breast  Wheel  ;  Horizontal  Wheel  ;  Barker's  Mill. 
Wind  Power  : — ^Vertical  Windmill ;  Adjustment  of 
Sails  ;  Horizontal  Windmill.  Steam  Power  : — 
Steam;  Applications  of  Steam  ;  By  Condensation  ; 
By  Generation  ;  By  Expansion  ;  The  Steam  En- 
gine ;  Boiler ;  Appendages  ;  Engine  ;  Noncon- 
densing  Engine  ;  Condensing  Engines  ;  Descrip- 
tion ;  Expansion  Engines  ;  Condenser;  Valves  ; 
Pistons  ;    Parallel  Motion  ;    Locomotive   Engine  ; 


CONTENTS.  5 

Power  of  the  Steam  Engine  ;  Projected  Improve- 
ments ;  Rotative  Engines  ;  Use  of  Steam  at  High 
Temperatures  ;  Use  of  Vapors  of  Low  Tempera- 
ture ;  Gas  Engines  ;  Steam  Carriages  ;  Steam 
Gun.  Gunpowder  : — Manufacture  ;  Detonation  ; 
Force  ;  Properties  of  a  Gun  :  Blasting.  Magnet- 
ic Engines, 81 

CHAPTER  XVII. 

ARTS  OF  CONVEYING  WATER. 

Of  Conducting  Water  : — Aqueducts  ;  Water  Pipes  5 
Friction  of  Pipes  ;  Obstruction  of  Pipes  ;  Syphon. 
Of  Raising  Water  :  —  Scoop  Wheel  ;  Persian 
Wheel  ;  Noria  ;  Ijj^e  Pump  ;  Hydreole  ;  Archi 
medes'  Screw  ;  Spiral  Pump  ;  Centrifugal  Pump  ; 
~  Common  Pumps  ;  Forcing  Pump  ;  Plunger  Pump  ; 
De  La  Hire's  Pump  ;  Hydrostatic  Press  ;  Lifting 
Pump  ;  Bag  Pump  ;  Double-acting  Pump  ;  Rol- 
ling Pump  ;  Eccentric  Pump  ;  Arrangement  of 
Pipes  ;  Chain  Pump  ;  Schemnitz  Vessels,  or  Hun- 
garian Machine  ;  Hero's  Fountain  ;  Atmospheric 
Machines  ;  Hydraulic  Ram.  Of  Projecting  Water  : 
—Fountains  ;  Fire  Engines  ;  Throwing  Wheel,    .   135 

CHAPTER  XVIII. 

ARTS  OF  COMBINING  FLEXIBLE  FIBRES. 

Theory  of  Twisting  ;  Rope  Making  ;  Hemp  Spin- 
ning. Cotton  Manufacture  : — Elementary  Inven- 
tions ;  Batting  ;  Carding  ;  Drawing  ;  Roving  ; 
Spinning  ;  Mule  Spinning  ;  Vv^arping  ;  Dressing  ; 
Weaving  ;  Twilling  ;  Double  Weaving  ;  Cross 
Weaving  ;  Lace  ;  Carpeting  ;  Tapestry  ;  Velvets 
Linens.       Woollens.      Felting.      Paper    Making. 

Bookbinding, .     .    164 

1* 


CONTENTS, 


CHAPTER  XIX. 

ARTS  OF  HOROLOGY. 

Sun  Dial  ;  Clepsydra  ;  Water  Clock  ;  Clock  Work  ; 
Maintaining  Power  ;  Regulating  Movement  ;  Pen- 
dulum ;  Balance  ;  Scapement  ;  Description  of  a 
Clock  ;   Striking  Part  ;  Description  of  a  Watch,       187 

CHAPTER  XX. 

ARTS  OF  METALLURGY. 

Extraction  of  Metals  ;  Assaying  ;  Alloys.  Gold  : — 
Extraction  ;  Cupellation  ;  Partif%  ;  Cementation  ; 
Alloy  ;  Working  ;  Gold  Beating  ;  Gilding  on  Met- 
als ;  Gold  Wire.  Silver  : — Extraction  ;  Working  • 
Coining  ;  Plating.  Copper  : — Extraction  ;  Work- 
ing. Brass  :  — Manufacture  ;  Buttons  ;  Pins  ; 
Bronze.  Lead  : — Extraction  ;  Manufacture  ;  Sheet 
Lead  ;  Lead  Pipes  ;  Leaden  Shot.  Tin  : — Block 
Tin  ;  Tin  Plates  ;  Silvering  of  Mirrors.  Iron  : — 
Smelting  ;  Crude  Iron  ;  Casting  ;  Malleable  Iron  ; 
Forging  ;  Rolling  and  Slitting  ;  Wire  Drawing  ; 
Nail  Making  ;  Gun  Making.  Steel  : — Alloys  of 
Steel  ;   Case  Hardening  ;  Tempering  ;   Cutlery,      208 

CHAPTER  XXI. 

ARTS  OF  VITRIFICATION. 

Glass  ;  Materials  ;  Crown  Glass  ;  Fritting  ;  Melt- 
ing ;  Blowing  ;  Annealing  ;  Broad  Glass  ;  Flint 
Glass  ;  Bottle  Glass  ;  Cylinder  Glass  ;  Plate 
Glass  ;  Moulding  ;  Pressing  ;  Cutting  ;  Stained 
Glass  ;  Enamelling  ;  Artificial  Gems  ;  Devitrifica- 


CONTENTS.  7 

tion  ;  Reaumur's  Porcelain  ;  Crystallo-Ceramie  ; 
Glass  Thread  ;  Remarks, 247 

CHAPTER  XXII. 

ARTS  OF  INDURATION  BY  HEAT. 

Bricks  ;  Pressed  Bricks  ;  Tiles  ;  Terra  Cotta  ;  Cru- 
cibles ;  Pottery  ;  Operations  ;  Stone  Ware ; 
White  Ware  ;  Throwing  ;  Pressing  ;  Casting  ; 
Burning  ;  Printing  ;  Glazing  ;  China  Ware  ;  Eu- 
ropean Porcelain  ;  Etruscan  Vases,     ....        262 

APPENDIX. 

Artesian  Wells.  Mines.  Depth  of  Mines.  Canals 
in  the  United  States.  Rail-Ways  in  the  United 
States.  Manufacture  of  Maple  Sugar.  Manufac- 
ture of  Beet  Sugar.  Voltaic  Electrical  Engraving. 
Photogenic  Drawing,         275 

Glossary,      .     .  ...  369 

Index,       .  ,     .  375 


THE  USEFUL  ARTS 


CHAPTER  XIV. 

ARTS    OF    LOCOAIOTIOX. 

Motioa  of  Animals,  Inertia,  Aids  to  Locomotion,  Wheel  Carnages^ 
Wheels,  Rollers,  Size  of  Wheels,  Line  of  Traction,  Broad  W^heels, 
Form  of  Wheels,  Axletrees,  Springs,  Attaching  of  Horses.  High- 
ways, Roads,  Pavements,  Wooden  Pavements,*  McAdam  Roads. 
Bridges,  1,  ^V'ooden  Bridges,  2,  Stone  Bridges,  3,  Cast-Iron  Bridges, 
4,  Suspension  Bridges,  5,  Floathig  Bridges.  Rail  Roads,  Edge 
Rail-way,  Tram  Road,  Single  Rail,  Passings,  or  Sidings,  Turn 
Plate,  Curves,  Propelling  Power,  Locomotive  Engines,  Stationary 
Engines-  Canals,  Embankments,  Aqueducts,  Tunnels,  Gates  and 
Weirs,  Locks,  Boats,  Size  of  Canals.  Sailing,  Form  of  a  Ship, 
Keel  and  Rudder,  Effect  of  the  Wind,  Stability  of  a  Ship,  Steam 
Boats,  Steam  Ships.  Diving  Bell,  Submarine  Navigation.  Aeros- 
tation,  Balloon,  Parachute. 

Animals,  of  the  more  perfect  kinds,  possess  the  power 
of  shifting  their  place,  at  will,  which  power  they  exercise, 
both  in  transporting  their  own  bodies,  and  in  conv^eying 
other  masses  of  matter.  The  chief  obstacles,  which  op- 
pose locomotion  or  change  of  place,  are,  gravity  and  fric- 
tion, the  last  of  which  is,  in  most  cases,  a  consequence 
of  the  first.  Gravity  confines  all  terrestrial  bodies  against 
the  surface  of  the  earth,  with  a  force  proportionate  to  the 
quantity  of  matter  which  composes  them.  Before  they 
can  be  removed  from  one  spot  of  this  surface,  to  another, 
Df  equal  height,  they  must  either  be  lifted  from  the  ground, 
igainst  the  force  of  gravity,  or  carried,  horizontally,  along 
rhe  surface,  resisting  with  a  degree  of  friction,  which  in- 
ireases  with  their  weight.  Most  kinds  of  mechanism, 
both  natural  and  artificial,  which  assist  locomotion,  are 
arrangements  for  obviating  the  effects  of  gravity  and  fric- 
lion. 


10  ARTS   OF  LOCOMOTION. 

J\Iotio7i  of  Animals. — Animals,  that  walk,  obviate  fric- 
tion, by  substituting  points  of  their  bodies,  instead  of  large 
surfaces  ;  and  upon  these  points  they  turn,  as  upon  cen- 
tres, for  the  length  of  each  step,  raising  themselves  wholly, 
or  partly,  from  the  ground,  in  successive  arcs,  instead  of 
drawing  themselves  along  the  surface.  The  hne  of  arcs, 
which  the  centre  of  gravity  describes,  is  converted  into 
an  easy,  or  undulating  hne,  by  the  compound  action  of  the 
different  joints.  As  the  feet  move  in  separate  hnes,  the 
body  has,  also,  a  lateral,  vibratory  motion.  A  man,  in 
walking,  puts  down  one  foot,  before  the  other  is  raised, 
but  not  in  running.  Quadrupeds,  in  walking,  have  three 
feet  upon  the  ground,  for  most  of  the  time  ;  in  trotting, 
only  two.  Animals,  which  w^alk  against  gravity,  as  the 
common  fly,  the  tree  toad,  &c.,  support  themselves  by 
suction,  using  cavities  on  the  under  side  of  their  feet, 
which  they  enlarge,  at  pleasure,  till  the  pressure  of  the  at- 
mosphere causes  them  to  adhere.  In  other  respects,  their 
locomotion  is  effected  like  that  of  other  walking  animals. 
Birds  perform  the  motion  of  flying,  by  striking  the  air, 
with  the  broad  surface  of  their  wings,  in  a  downward,  and 
backward,  direction,  thus  propelling  the  body  upward,  and 
forward.  After  each  stroke,  the  wings  are  contracted, 
or  slightly  turned,  to  lessen  their  resistance  to  the  atmos- 
phere, then  raised,  and  spread  anew.  The  downward 
stroke,  also,  being  more  sudden  than  the  upward,  is  more 
resisted  by  the  atmosphere.  The  tail  of  birds  serves  as 
a  rudder,  to  direct  the  course  upward,  or  downward. 
When  a  bird  sails  in  the  air,  w^ithout  moving  the  wings,  it 
is  done,  in  some  cases,  by  the  velocity  previously  acquired, 
and  an  oblique  direction  of  the  wings,  upward  ;  in  others, 
by  a  gradual  descent,  with  the  wings  slightly  turned  in  an 
oblique  direction,  downward.  Fishes,  in  swimming  for- 
ward, are  propelled  chiefly  by  strokes  of  the  tail,  the  ex- 
tremity of  which,  being  bent  into  an  oblique  position,  pro- 
pels the  body  forward,  and  laterally,  at  the  same  time.  The 
lateral  motion  is  corrected  by  the  next  stroke,  in  the  op- 
posite direction,  while  the  forward  course  continues.  The 
fins  serve,  partly,  to  assist  in  swimming,  but,  chiefly,  to 
balance  the  body,  or  keep  it  upright  ;  for  the  centre  of 


INERTIA.  11 

gravity  being  nearest  the  back,  a  fish  turns  over,  when  it 
is  dead,  or  disabled.*  Some  other  aquatic  animals,  as 
leeches,  swim  with  a  sinuous,  or  undulating,  motion  of  the 
body,  in  which  several  parts,  at  once,  are  made  to  act 
obliquely,  against  the  water.  Serpents,  in  like  manner, 
advance,  by  means  of  the  winding,  or  serpentine,  direction 
which  they  give  to  their  bodies,  and  by  which  a  succes- 
sion of  oblique  forces  is  brought  to  act  against  the  ground. 
Sir  Everard  Home  is  of  opinion,  that  serpents  use  their 
ribs,  in  the  manner  of  legs,  and  propel  the  body  forwards, 
by  bringing  the  plates,  on  the  under  surface  of  the  body, 
to  act,  successively,  like  feet,  against  the  ground. f  Some 
worms  and  larvas,  of  slow  motion,  extend  a  part  of  their 
body  forwards,  and  draw  up  the  rest  to  overtake  it ;  some 
performing  this  motion,  in  a  direct  line,  others,  in  curves. 

When  land  animals  swim  in  water,  they  are  supported, 
because  their  whole  weight,  with  the  lungs  expanded  with 
air,  is  less  than  that  of  an  equal  bulk  of  water.  The  head, 
however,  or  a  part  of  it,  must  be  kept  above  water,  to 
enable  the  animal  to  breathe  ;  and  to  effect  this,  and  also 
to  make  progress  in  the  water,  the  hmbs  are  exerted,  in 
successive  impulses,  against  the  fluid.  Quadrupeds  and 
birds  swim  with  less  effort  than  man,  because  the  weight 
of  the  head,  which  is  carried  above  water,  is,  in  them,  a 
smaller  proportional  part  of  the  whole,  than  it  is  in  man. 

Inertia. — In  consequence  of  the  action  of  gravity  upon 
bodies,  their  inertia  becomes  a  greater  obstacle  to  loco- 
motion than  it  would  otherwise  be.  Every  body  tends, 
by  its  inertia,  to  preserve  a  state  of  rest,  if  it  is  still,  and 
of  uniform  rectilinear  motion,  if  it  is  not  still.  Changes, 
therefore,  not  only  from  rest  to  motion,  but  also  changes 

*  The  swimming  bladder,  which  exists  in  most  fishes,  though  not  in 
all,  is  supposed  to  have  an  agency  in  adapting  the  specific  gravity  of 
the  fish  to  the  particular  depth,  in  which  it  resides.  The  power  of  the 
animal  to  rise  or  sink,  by  altering  the  dimensions  of  this  organ,  haa 
been,  with  some  reason,  disputed. 

t  Lectures  on  Comparative  Anatomy,  vol.  i.  p.  116,  &c.  Sir  E 
Home  deduces  this  fact  from  the  anatomy  of  the  animal,  and  from  the 
movements  which  he  perceived,  in  suffering  a  large  coluber  to  crawl 
over  his  hand.  The  ribs  appeared  to  be  raised,  spread,  carried  for 
ward,  depressed,  and  pushed  backward,  successively. 


12  ARTS   OF  LOCOMOTION. 

of  direction,  and  changes  of  speed,  are  resisted  by  the 
force  of  inertia.  Bodies  moving  upon  the  earth's  surface 
are  obhged,  by  their  gravity,  to  accommodate  their  mo- 
tions to  the  irregularities  of  this  surface,  and,  consequent- 
ly, to  change,  often,  both  their  direction  and  velocity  The 
inertia  thus  becomes  a  continual  source  of  expenditure  of 
power,  although  it  would  not  be  so,  if  bodies  moved  at  a 
uniform  rate,  and  in  a  straight  course. 

Aids  to  Locomotion. — All  animals  are  provided,  by 
Nature,  with  organs  of  locomotion  best  adapted  to  their 
structure  and  situation  ;  and  it  is  probable  that  no  animal, 
man  not  being  excepted,  can  exert  his  strength  more  ad- 
vantageously, by  any  other  than  the  natural  mode,  in  moving 
himself  over  the  common  surface  of  the  ground.*  Thus 
walking-cars,  velocipedes,  &c.,  although  they  m.ay  enable 
a  man  to  increase  his  velocity  in  favorable  situations,  for  a 
short  time,  yet  they  actually  require  an  increased  expen- 
diture of  power,  for  the  purpose  of  transporting  the  ma- 
chine made  use  of,  in  addition  to  the  weight  of  the  body. 
When,  however,  a  great  additional  load  is  to  be  transport- 
ed with  the  body,  a  man,  or  animal,  may  derive  much 
assistance  from  mechanical  arrangements. 

Wheel  Carriages. — For  moving  weights  over  the  com 
mon  ground,  with  its  ordinary  asperities  and  inequalities  of 
substance  and  structure,  no  piece  of  inert  mechanism  is 
so  favorably  adapted,  as  the  wheel-carriage.  It  was  in- 
troduced into  use,  in  very  early  ages,  as  affording  a  facil- 
ity for  the  carrying  of  heavy  loads,  and,  finally,  for  trans 
porting  man  himself;  not  by  his  own  powers,  but  by  the 
strength  of  other  animals,  which  he  had  subjugated  to  his 
use.  Chariots  were  used  in  war,  and  wagons  in  agricul- 
ture, at  a  very  remote  period. 

Wheels. — The  mechanical  action  of  wheels,  applied  to 
locomotive  carriages,  is  twofold.  They  diminish  friction, 
and,  also,  surmount  obstacles,  or  inequalities,  of  the  road, 
with  more  advantage  than  bodies  of  any  other  form,  in 
their  place,  could  do.  The  friction  is  diminished,  by 
transferring  it  from  the  surface  of  the  ground  to  the  cen- 

*  This  remark,  of  course,  does  not  apply  to  situations  in  which  fric- 
tion is  obviated,  as  upon  water,  ice,  rail-roads,  &c. 


ROLLERS. SIZE   OF   WHEELS  13 

tre  of  the  wheel,  or  rather  to  the  place  of  contact,  between 
the  axletree  and  the  box  of  the  wheel.  So  that  it  is  les- 
sened, by  the  mechanical  advantage  of  the  lever,  in  the 
proportion,  which  the  diameter  of  the  axletre>3  bears  to  the 
diameter  of  the  wheel.  The  rubbing  surfaces,  also, 
beiig  kept  polished,  and  smeared  with  some  unctuous 
substance,  are  in  the  best  possible  condition  to  resist 
friction. 

In  like  manner,  the  common  obstacles,  that  present 
themselves  in  the  public  roads,  are  surmounted  by  a  wheel, 
with  pecuhar  facility.  As  soon  as  the  wheel  strikes 
against  a  stone,  or  similar  hard  body,  it  is  converted  into 
a  lever,  for  lifting  the  load  over  the  resisting  object.  If 
an  obstacle,  eight  or  ten  inches  in  height,  were  presented 
to  the  body  of  a  carriage,  unprovided  with  wheels,-  it 
would  stop  its  progress,  or  subject  it  to  such  violence  as 
would  endanger  its  safety.  But,  by  the  action  of  a  wheel, 
the  load  is  lifted,  and  its  centre  of  gravity  passes  over,  in 
the  direction  of  an  easy  arc,  the  obstacle  furnishing  the 
fulcrum,  on  which  the  lever  acts. 

Rollers. ^R^oWers,  placed  under  a  heavy  body,  diminish 
the  friction  in  a  greater  degree  than  wheels,  provided 
they  are  true  spheres,  or  cylinders,  without  any  axis,  on 
which  they  are  constrained  to  move.  If  the  rollers  be 
perfectly  elastic,  and,  also,  the  plane  upon  which  they 
move,  there  will  be  no  sliding  friction,  whatever  ;  whereas 
the  wheel  always  rubs  at  its  axis.  But  an  offset  for  this 
advantage  is  found  in  the  circumstance,  that  the  wheel 
maintains  its  relative  place,  in  regard  to  the  load,  while  the 
roller  constantly  falls  behind,  and  is  obhged  to  be  taken 
up  and  replaced,  at  an  expense  of  power.  A  cyhndrical 
roller,  likewise,  occasions  friction,  whenever  its  path  de- 
viates, in  the  least,  from  a  straight  line. 

Size  of  Wheels. — The  mechanical  advantages  of  a 
wheel  are  proportionate  to  its  size  ;  and  the  larger  it  is, 
the  more  effectually  does  it  diminish  the  ordinary  resist- 
ances. A  large  wheel  will  surmount  stones,  and  similar 
obstacles,  better  than  a  small  one  ;  since  the  arm  of  the 
iever,  on  which  the  force  acts,  is  longer,  and  the  curve, 
described  by  the  centre  of  the  load,  is  the  arc  of  a  iar- 
II.  2  XII. 


14  ARTS  OF  LOCOMOTION. 

ger  circle,  and,  of  course,  the  ascent  is  more  gradual  and 
easy.* 

A.  further  advantage  is  derived  from  the  circumstance, 
that,  in  passing  over  holes,  ruts,  or  excavations,  a  large 
wheel  sinks  less  than  a  small  one,  and,  consequently,  occa- 
sions less  jolting,  and  expenditure  of  power.  The  \v«ar, 
also,  of  small  wheels,  exceeds  that  of  larger  ones ;  for,  if 
we  suppose  a  wheel  to  be  three  feet  in  diameter,  it  will 
turn  round  twice,  while  a  wheel,  six  feet  in  diameter,  turns 
round  once.  Of  course,  its  tire  will  come  twice  as  often 
in  contact  with  the  ground,  and  its  spokes  will  twice  as 
often  have  to  support  the  weight  of  the  load.  So,  that, 
by  calculation,  it  should  last  but  half  the  length  of  time. 

On  these  accounts,  it  would  be  advantageous  to  aug- 
ment the  diameter  of  wheels  to  a  great  extent,  were  it  not 
for  certain  practical  limits,  which  it  is  not  found  useful  to 
exceed.  One  of  these  is  found  in  the  nature  of  the  ma- 
terials, which  we  are  obliged  to  use,  and  which,  if  em- 
ployed to  make  wheels  of  great  size,  at  the  same  time 
preserving  the  requisite  strength,  would  render  them  cum- 
bersome, and  too  heavy  for  use.f  Another  reason,  for 
regulating  the  size  of  wheels  by  a  limited  standard,  arises 
from  the  relative  size  of  the  animals,  commonly  employed 
for  draught.  A  wheel  should  seldom  be  of  such  dimen- 
sions, that  its  centre  would  exceed,  in  height,  the  breast  of 
the  horse,  or  other  animal,  by  which  it  is  drawn  ;  because, 
if  this  were  the  case,  the  horse  would  draw  obhquely 
downward,  as  well  as  forward,  and  expend  a  part  of  his 
strength  in  acting  against  the  ground. 

Line  of  Traction. — In  practice,  it  is  even  found  neces- 
sary, to  place  the  point  of  draught,  or  centre  of  the  wheels, 
lower  than  the  middle  of  the  horse's  breast,  for  various 
reasons.  1.  The  shape  of  the  animal's  shoulders  requires 
this  direction.  2.  The  horse  exerts  a  greater  force,  in 
proportion,  as  the  line  of  draught  passes  near  the  fulcrum, 

*  If  the  plane,  on  which  a  carriage  moves,  and  the  line  of  draught  be 
both  horizontal,  the  advantage,  for  surmounting  an  immovable  obstacle 
of  a  given  height,  is  as  the  square  root  of  the  radius  of  the  wheel. — Se« 
Flayfair's  Outlines  of  JVatural  Philosophy,  vol.  i.  p.  103. 

t  See  the  article.  Limit  of  Bulk,  p.  48 


BROAD  WHEELS.  15 

which  is  in  his  hind  feet.  3.  If  a  horse  draws  obliquely 
upward,  a  part  of  his  force  is  employed  in  lessening  the 
pressure  on  the  ground,  and,  to  answer  this  purpose  most 
effectually,  it  has  been  remarked,  that  the  inclination  of 
the  traces,  or  shafts,  ought  to  be  the  same  with  that  of  a 
road,  upon  which  the  carriage  would  just  descend  by  its 
own  weight.*  According  to  Dr.  Gregory,  a  power,  which 
moves  a  sliding  body  along  a  horizontal  plane,  acts  with 
the  greatest  advantage,  as  far  as  friction  is  concerned, 
when  the  line  of  direction  makes  an  angle  of  about  eigh- 
teen and  a  half  degrees  with  the  plane. f  M.  Deparcieux 
states,  from  experiments  with  carriages,  that  the  angle, 
made  by  the  trace  with  a  horizontal  line,  should  be  one  of 
fourteen  or  fifteen  degrees.  4.  Another  reason,  for  in- 
clining the  hne  of  draught,  is,  that  a  horse  depresses  his 
body,  in  proportion  to  the  force  he  is  obliged  to  exert,  in 
order  that  he  may  bring  his  own  weight  to  act  more  advan- 
tageously upon  the  load.  M.  Deparcieux  has  demon- 
strated, that  animals  draw  through  the  medium  of  their 
weight,  in  all  our  common  vehicles  ;  and  this  fact  becomes 
obvious,  when  we  consider,  that  if  a  horse  had  no  weight, 
he  would  be  unable  to  draw,  but  would  simply  be  raised 
on  his  hind  feet,  by  any  exertion  to  advance,  while  in  his 
harness. 

In  the  foregoing  considerations,  it  is  necessary  to  re- 
collect, that  the  conditions,  which  enable  a  horse  to  exert 
his  greatest  force,  are  not  those  which  promote  his  greatest 
velocity,  and  that  the  means  of  increasing  his  speed  are 
obtained,  as  in  other  cases,  by  the  sacrifice  of  power. 

When  there  are  four  wheels,  the  line  of  draught  ought 
to  be  directed  to  a  point  between  the  two  axletrees,  or, 
rather,  to  a  point  directly  under  the  centre  of  gravity  of 
the  load  ;  and  such  a  line  should  always  pass  above  the 
axle  of  the  fore  wheels. 

Broad  Wheels. — Much  controversy  has  existed  in  re- 
gard to  the  comparative  utility  of  wheels  having  a  broad, 
or  a  narrow,  circumference.  The  disadvantages  of  broad 
wheels  are,  that  they  are* heavier  than  narrow  ones,  that 

*  Young's  Natural  Philosophy,  vol.  i.  p.  216. 
t  Treatise  on  Mechanics,  vol  ii  p.  18. 


16  ARTS   OF  LOCOMOTION 

they  are  more  expensive,  and  that  they  include  in  their 
path  a  greater  number  of  stones,  or  projecting  obstacles. 
Their  advantages  are,  that  they  pass  more  easily  over 
ruts  and  holes,  and  that^  in  soft  and  sandy  roads,  they  sink 
to  a  smaller  depth.*  But  the  great  benefit  which  results 
from  broad  wheels  is  of  an  indirect  kind,  and  arises  from 
the  improvement  of  the  roads,  which  takes  place  under 
their  use.  They  tend  to  prevent  deep  and  narrow  ruts, 
and  act  as  rollers,  in  levelling  the  surface. 

Form  of  Wheels. — If  roads  w^ere,  in  all  cases,  level  and 
smooth,  wheels  should  be  made  exactly  cylindrical,  or 
with  all  their  spokes  parallel  to  the  same  plane.  But, 
since  the  unequal  surface  of  most  roads  exposes  carriages 
to  frequent  and  sudden  changes  of  position,  it  is  found 
advantageous  to  make  the  wheels  a  litde  conical,  or,  as  it 
is  commonly  termed,  dishing,  so  that  the  spokes  may  all 
diverge,  with  their  extremities  from  the  carriage.  In  this 
case,  whenever  the  carriage  is  thrown  into  an  inclined 
position,  and  the  centre  of  gravity  shifted  towards  one 
wheel,  the  spokes  on  the  under  side  of  that  wheel,  become 
more  nearly  vertical,  and  are  in  a  more  advantageous 
position  to  sustain  the  pressure.  This  w^ill  be  seen  in 
Fig.  94,  on  the  opposite  page.  In  muddy  roads,  there 
is  a  convenience  attending  the  dished  wheel,  in  having  its 
circumference  further  from  the  body  of  the  carriage,  than 
that  of  a  straight  wheel,  upon  the  same  hubb,f  would  be. 
Some  disadvantages,  at  the  same  time,  attend  upon  this 
form  of  the  w^ieel,  the  principal  of  which  is,  the  increase 
of  friction  which  it  occasions.  A  conical  wheel,  if  left  to 
itself,  tends  to  travel  in  a  circle,  round  a  point,  where  the 
apex  of  the  cone  would  be  situated.  If  it  is  obliged  to 
advance  in  a  straight  line,  it  has  a  degree  of  lateral  motion 
and  friction,  which  increases  in  proportion  as  it  deviates 
from  the  cyhndrical  form.     In  common  cases,  a  slight 

*  The  latter  advantage,  however,  is  of  a  more  equivocal  kind  than 
appears  at  first  view  ;  for  although  they  sink  less  deeply,  they  displace 
more  earth  in  sinking  to  the  same  depth.  Still,  however,  the  advan- 
tage, upon  calculation,  remains  on  the  side  of  the  broad  wheel. 

t  This  word,  instead  of  ?iai'C,  is  so  generally  used  in  this  country,  tha^ 
It  would  be  a  useless  refinement  to  avoid  it.  The  same  is  true  of  tlw 
woTd  factory  for  manufactory,  and  also  of  many  mechanical  terms. 


AXLETREES SPRINGS,   ETC.  17 

degree  of  the  dishing  form  is  best,  but  it  should  never  be 
carried  to  such  an  extent,  as  to  create  much  friction,  or 
endanger  the  bending  of  the  spokes. 

In  the  annexed  figure,  (94,)  A  represents  the  cyhndri- 
cal,  and  B  the  dished,  form  of  the  wheel. 

Fis.  94. 


Axletrees. — When  wheels  are  perfectly  upright,  the 
ends  of  the  axles  should  be  cylindrical ;  but,  in  dished 
wheels,  they  are  made  conical,  and  inclined  downward,  so 
as  to  make  their  under  surface  horizontal.  In  this  case, 
the  wheels  spread  most  at  top,  and  the  lower  spokes  are 
most  nearly  vertical.  The  ends  of  the  axletree  are  often 
inclined  a  httle  forward,  which  arrangement  causes  the 
wheels  to  run  inward,  and  prevents  them  from  pressing 
on  the  hnch-pin.  The  friction,  however,  is  increased. 
In  some  locomotive  carriages,  the  axle  is  fixed  to  both 
wheels,  and  turns  with  them.  This  mode  of  connexion 
causes  great  strain  and  friction,  whenever  the  path  is  in 
any  other  than  a  straight  hue,  from  the  necessity,  which 
IS  produced,  that  the  wheels  should  keep  pace  with  each 
other,  in  their  revolutions. 

Springs. — The  effect  of  suspending  a  carriage  on 
springs  is,  to  equalize  the  motion,  by  causing  every  change 
to  be- more  gradually  communicated  to  it,  and  to  obviate 
shocks,  by  converting  percussion  into  pressure..  Springs 
are  not  only  useful  for  the  convenience  of  passengers,  but 
they  also  diminish  the  labor  of  draught ;  for,  whenever  a 
wheel  strikes  a  stone,  it  rises  against  the  pressure  of  the 
spring,  in  many  cases,  without  materially  disturbing  the 
load  ;  whereas,  without  the  spring,  the  load,  or  a  part  of 
it,  must  rise  with  every  jolt  of  the  wheel,  and  will  resist 
this  change  of  place,  with  a  degree  o^  inertia  proportionate 
to  the   weight  and  the   suddenness  of  the   percussion. 


IS 


ARTS   OF  LOCOMOTION. 


Hence,  springs  are  highly  useful,  in  baggage  wagons,  ard 
other  vehicles,  used  for  heavy  transportation.* 

Attaching  of  Horses. — Horses  draw  most  advantage  • 
ously,  when  they  are  either  single,  or  harnessed  abreast 
of  each  other.  When  two  horses  draw  side  by  side,  they 
are  equally  near  to  the  load,  and  have  the  same  line  of 
traction.  If  their  traces  are  attached,  as  is  frequently  done, 
to  hooks  on  the  ends  of  a  crossbar,  which,  in  its  turn,  is 
connected  to  the  carriage  by  a  staple,  projecting  behind, 
a  compensation  will  be  thus  made  for  any  difference  in  the 
strength,  or  activity,  of  the  animals.     In  Fig.  95,  the  cen- 


L 


Fig.  95. 


A. 
C 


B 


F 


tre,  E,  upon  which  the  bar  moves,  is  considerably  behind 
the  points  of  attachment,  x\  and  B.  Hence,  w^hen  one  end 
falls  back,  so  that  the  arm,  AB,  assumes  the  poshion,  CD, 
the  foremost  horse  will  have  the  disadvantage  of  acting 
by  a  lever  equal  only  to  EF,  while  the  other  horse  acts 
by  a  lever  equal  to  EC  In  the  narrow  streets  of  cities, 
a  custom  has  arisen  of  harnessing  draught  horses  before 
each  other,  in  a  single  line,  probably  for  the  sake  of  room, 
and  the  convenience  of  the  driver.  But,  in  this  situation, 
only  the  shaft  horse  has  an  advantageous  hne  of  draught. 
The  remaining  horses  draw  nearly  in  a  horizontal  line,  and, 
of  course,  at  a  disadvantage.  Besides  this,  the  foremost 
horses,  being  attached  to  the  ends  of  the  shafts,  do  not  act 
directly  upon  the  load,  hut  expend  a  part  of  their  force 

Fig.  96. 


See  a  paper  by  Mr. Gilbert,  in  Brande's  Journal,  vol.  xix. 


HIGHWAYS. ROADS. PAVEMENTS.  19 

in  vertical  pressure,  upon  the  back  of  the  shaft  horse,  which 
is  increased  in  drays,  sleds,  and  all  low  carriages.  This 
will  be  seen  by  inspecting  Fig.  96,  where  it  is  obvious,  that 
the  hne  of  draught  of  the  first  horse  cannot  become  direct, 
without  crippling  down  the  shaft  horse.  The  best  mode 
of  remedying  this  difficulty,  would  apparently  be,  to  attach 
the  traces  of  the  forward  horse  to  a  strong  hook,  project- 
ing downward  from  the  end  of  each  shaft,  so  as  to  bring 
the  traces  into  the  proper  line  of  traction,  by  directing  them 
more  nearly  towards  the  centre  of  the  wheels.  It  is  true, 
that  the  shaft  horse  derives  a  certain  degree  of  mechani- 
cal advantage  from  vertical  pressure,  hke  that  which  would 
result  from  an  increase  of  his  weight.  Yet  this,  although 
useful  in  short  exertions,  is  not  so,  when  continued  through 
a  day's  fatigue. 

HIGHWAYS. 

Roads. — Roads,  intended  for  the  passage  of  wheel-car- 
nages, are  made  more  level,  and  of  harder  materials,  than 
the  rest  of  the  ground.  In  roads,  the  travel  on  which  does 
not  authorize  great  expense,  natural  materials  alone  are  em- 
ployed, of  which  the  best  are  hard  gravel  and  very  small 
stones.  The  surface  of  roads  should  be  nearly  flat,  with 
gutters  at  the  sides,  to  facihtate  the  running  ofFof  water.  If 
the  surface  is  made  too  convex,  it  throws  the  weight  of  the 
load  unequally  upon  one  wheel,  and  also  that  of  the  horses 
on  one  side,  whenever  the  carriage  takes  the  side  of  the 
road.  Hence,  drivers  prefer  to  take  the  middle,  OBtop,  of 
the  road,  and,  by  pursuing  the  same  track,  occasion  deep 
ruts.  The  prevention  of  ruts  is  best  effected  by  flat  and 
solid  roads,  and  by  the  use  of  broad  wheels.  It  would 
also  be  further  effected,  if  a  greater  variety  could  be  intro- 
duced in  the  width  of  carriages.  Embankments  at  the 
sides,  to  keep  the  earth  from  sHding  down,  are  best  made^ 
by  piling  sods  upon  each  other,  like  bricks,  with  the  grassy 
surface  at  right  angles  with  the  surface  of  the  bank.  But 
stone  walls  are  preferable  for  this  purpose,  when  the  ma- 
terial can  be  readily  obtained. 

Pavements. — Pavements  are  stone  coveriiags  ol  the 
ground,  chiefly  employed  in  populous  cities,  and  the  most 


20  ARTS   OF  LOCOMOTION. 

frequented  roads.  Among  us,  they  are  made  of  pebbles, 
of  a  roundish  form,  gathered  from  the  sea-beach.  They 
should  consist  of  the  hardest  kinds  of  stone,  such  as  gran- 
ite, sienite,  &c.  It  flat  stones  are  used,  they  require  to 
be  artificially  roughened,  to  give  secure  foothold  to  horses. 
In  Milan,  and  some  other  places,  tracks  for  wheels  are 
made  of  smooth  stones,  while  the  rest  of  the  way  is  paved 
with  small,  or  rough,  stones.* 

The  advantage  of  a  good  pavement  consists,  not  only  in 
its  durability,  but  in  the  facility  wuth  which  transportation  on 
it  is  effected.  Hors«s  draw  more  easily  on  a  pavement, 
than  on  a  common  road,  because  no  part  of  their  power  is 
lost,  in  changing  the  form  of  the  surface.  The  disadvan- 
tages of  pavements  consist  in  their  noise,  and  in  the  wear 
which  they  occasion  of  the  shoes  of  horses,  and  tires  of 
wheels.  They  should  never  be  made  of  pebbles  so  large  as 
to  produce  much  jolting,  by  the  breadth  of  the  interstices. f 

Wooden  Pavements,  made  of  hexagonal  blocks  of  wood, 
have  been  introduced  in  some  of  our  cities.  They  have 
been  found  more  free  from  dust  and  noise  than  other  pave- 
ments. They  are  placed  with  the  grain  of  the  wood  per- 
pendicular to  the  ground,  to  prevent  splintering,  and  give 
better  foothold.  The  most  hard  and  durable  woods  are 
best ;  but  the  cheaper  kinds  are  more  used,  for  economy. 

McMam  Roads. — The  system  of  road-making,  which 
takes  its  name  from  Mr.  McAdam,  combines  the  advan- 
tages of  the  pavement  and  gravel  road.  The  McAdam 
roads  ajre  made  entirely  of  hard  stones,  such  as  granite, 
flint,  &c.,  broken  up,  with  hammers,  into  small  pieces,  not 
exceeding  an  inch  in  diameter.  These  fragments  are 
spread  u^ron  the  ground,  to  the  depth  of  from  six  to  ten 
inches.     At  first,  the  roads  thus  made  are  heavy,  and  la- 

*  The  streets  of  many  of  the  ancient  cities  were  paved,  as  those  of 
Rome,  Pompeii,  &c.  But  the  streets  of  London  were  not  paved  in  tne 
eleventh  century,  nor  those  of  Paris  in  the  twelfth. 

t  Mr  Telford  has  constructed,  in  England,  a  kind  of  paved  road,  in 
*vhich  the  foundation  consists  of  a  pavement  of  rough  stones  and  frag- 
ments, having  their  points  upward.  These  are  covered  with  very  small 
Btone  fragments,  and  gravel,  for  the  depth  of  four  inches,  the  whole  of 
which,  when  rammed  down  and  consolidated,  forms  a  hard,  smooth, 
and  durahle,  road. 


BRIDGES. WOODEN  BRIDGES.  21 

borious  to  pass  ;  but,  in  time,  the  stones  become  consol- 
idated, and  form  a  mass  of  great  hardness,  smoothness, 
and  permanency.  From  the  manner  in  which  the  stones 
overlap  each  other,  each  stone,  at  !he  surface,  may  be 
considered  as  the  apex  of  a  pyramid,  so  that  it  cannot  be 
driven  downward,  without  carrying  before  it  a  base  of, 
perhaps,  a  foot  square,  as  will  be  seen  by  Fig.  97.     The 

Fi^.  97. 


Stones  become  partly  pulverized,  by  the  action  of  carriage 
wheels,  and  partly  imbedded  in  the  earth  beneath  them. 
The  consohdation  seems  to  be  owing  to  the  angular  shape 
of  the  fragments,  which  prevents  them  from  rolling  in  tbeii 
beds,  after  the  insterstices  between  them  are  filled.  Mr. 
McAdam  advises,  that  no  other  material  should  be  added 
to  the  broken  stones,  apparently  with  a  view  to  prevent 
the  use  of  clay  and  chalk,  which  abound  in  England.  It 
appears,  however,  that  a  little  clean  gravel,  spread  upon 
the  stones,  causes  them  to  consolidate  more  quickly,  and 
has  the  good  effect  of  excluding  the  light  street  dirt,  which, 
otherwise,  never  fails  to  become  incorporated,  in  large 
quantities,  among  the  stones. 

BRIDGES. 

The  construction  of  small  bridges  is  a  simple  process, 
while  that  of  large  ones  is,  under  certain  circumstances, 
extremely  difficult,  owing  to  the  fact,  that  the. strength  of 
materials  does  not  increase  in  proportion  to  their  weight, 
and  that  there  are  limits,  beyond  which  no  structure  of 
the  kind  could  be  carried,  and  withstand  its  own  gravity. 
Bridges  differ,  in  their  construction,  and  in  the  materials 
of  which  they  are  composed.  The  principal  varieties 
are  the  following. 

1.     IVooden  Bridges. — These,  when  built  over  sha\- 


22  AKTS   OF  LOCOMOTION. 

low  and  sluggish  streams,  are  usually  supported  upon  piles, 
driven  into  the  mud,  at  short  distances,  or  upon  frames 
of  timber.  But,  in  deep  and  powerful  currents,  it  is  ne- 
cessary to  support  them  on  strong  3tone  piers,  and  abut- 
ments, built  at  as  great  a  distance  as  practicable  from 
each  other.  The  bridge,  between  these  piers,  consists  of 
a  stifi'  frame  of  carpentry,  so  constructed,  with  reference 
to  its  material,  that  it  may  act  as  one  piece,  and  may  not 
bend,  or  break,  with  its  own  weight,  and  any  additional 
load,  to  which  it  may  be  exposed.  When  this  frame  is 
straight,  the  upper  part  is  compressed^  by  the  weight  of 
the  whole,  while  the  lower  part  is  extended^  like  the  tie- 
beam  of  a  roof.  But  the  strongest  wooden  bridges  are 
made  with  curved  ribs,  which  rise  above  the  abutments, 
in  the  manner  of  an  arch,  and  are  not  subjected  to  a  lon- 
gitudinal strain,  by  extension.  These  ribs  are  commonly 
connected  and  strengthened  with  diagonal  braces,  keys, 
bolts,  and  straps  of  iron.  The  flooring  of  the  bridge  may 
be  either  laid  above  them,  or  suspended,  by  trussing,  un- 
derneath them.  Wooden  bridges  are  common  in  this 
country,  and  some  of  them  are  of  large  size.  One  of  the 
most  remarkable  is  the  upper  Schuylkill  bridge,  at  Phil- 
adelphia, which  consists  of  a  single  arch,  the  span  of 
which  is  three  hundred  and  forty  feet. 

2.  Stone  Bridges. — These,  for  the  most  part,  consist 
of  regular  arches,  built  upon  stone  piers,  constructed  in 
the  water,  or  upon  abutments  at  the  banks.  Above  the 
arches  is  made  a  level,  or  sloping,  road.  From  the  nature 
of  the  material,  these  are  the  most  durable  kind  of  bridges  ; 
and  many  are  now  standing,  which  were  built  by  the  an- 
cient Romans.  Several  of  the  stone  bridges  across  the 
Thames,  at  London,  are  distinguished  for  elegance  and 
strength.  The  stone  piers,  on  which  bridges  are  support- 
ed, require  to  be  of  great  solidity  ;  especially,  when  ex- 
posed to  rapid  currents,  or  to  floating  ice.  Piers  are 
usually  built  with  their  greatest  length  in  the  direction  of 
the  stream,  and  with  their  extremities  pointed  or  curved, 
so  as  to  divide  the  water,  and  allow  it  to  glide  easily  past 
them.  In  building  piers,  it  is  often  necessary  to  exclude 
the  water,  by  means  of  a  coffer-dam.    This  is  a  temporary 


CAST-IRON  BRIDGES,   ETC.  23 

enclosure,  formed  by  a  double  wall  of  piles  and  planks, 
having  their  interval  filled  with  clay.  The  interior  space 
is  made  dry  by  pumping,  and  kept  so,  till  the  structure  is 
finished. 

3.  Cast  Iron  Bridges. — These  have  been  constructed 
in  England  out  of  blocks,  or  frames,  of  cast-iron,  so  shap- 
ed, as  to  fit  into  each  other,  and,  collectively,  to  form  ribs 
and  arches.  These  bridges  possess  great  strength,  but 
are  hable  to  be  disturbed  by  the  expansion  and  contrac- 
tion of  the  metal  with  heat  and  cold. 

4.  Suspension  Bridges. — In  these,  the  flooring,  or 
main  body  of  the  bridge,  is  supported,  on  strong  iron 
chains,  or  rods,  hanging  in  the  form  of  an  inverted  arch, 
from  one  point  of  support  to  another.  The  points  of 
support  are  the  tops  of  strong  pillars,  or  small  towers, 
erected  for  the  purpose.  Over  these  pillars,  the  chain 
passes,  and  is  attached,  at  each  extremity  of  the  bridge, 
to  rocks,  or  massive  frames  of  iron,  firmly  secured  under 
ground.  The  great  advantage  of  suspension  bridges  con- 
sists in  their  stability  of  equilibrium,  in  consequence  of 
which,  a  smaller  amount  of  materials  is  necessary  for  their 
construction,  than  for  that  of  any  other  bridge.  If  a  sus- 
pension bridge  be  shaken,  or  thrown  out  of  equilibrium, 
it  returns,  by  its  weight,  to  its  proper  place  ;  whereas  the 
reverse  happens  in  bridges  which  are  built  above  the  level 
of  their  supporters.  One  of  the  most  remarkable  suspen- 
sion bridges,  is  that  over  the  Menai  strait,  on  the  coast 
of  Wales,  the  span  of  which,  or  rather  the  water-way,  is 
five  hundred  feet,  and  the  distance  between  the  points  of 
support,  or  centre  of  the  piers,  five  hundred  and  sixty 
feet.  It  is  suspended  by  four  wrought-iron  cables,  which 
pass  over  rollers,  on  the  tops  of  the  pillars,  and  are  fixed 
to  iron  frames,  under  ground,  which  are  kept  down  by 
masonry. 

5.  Floating  Bridges. — Upon  deep  and  sluggish  water, 
stationary  rafts  of  timber  are  sometimes  employed,  ex- 
tending from  one  shore  to  another,  and  covered  with 
planks,  so  as  to  form  a  passable  bridge.  In  military  op- 
erations, temporary  bridges  are  often  formed  by  planks 
laid  upon  boats,  pontoons,  and  other  buoyant  supporters. 


24  ARTS   OF  LOCOMOTION. 


RAIL-ROADS. 


In  the  best  constructed  public  roads,  a  great  amount 
of  power  is  expended,  in  overcoming  the  disad^vantages 
which  are  inseparable  from  their  construction,  and  the 
nature  of  their  materials.  The  chief  loss  of  power  de- 
pends on  the  continual  change  of  form,  which  carriages 
occasion  in  roads,  by  the  crushing  of  stones,  cutting  of 
ruts,  and  other  displacements  of  the  material  of  which  the 
load  is  made  ;  which  processes  serve  to  consume  power, 
without  forwarding  the  progress  of  the  carriage. 

The  object  of  a  rail-road  is  to  furnish  a  hard,  smooth, 
and  unchanging,  surface,  for  wheels  to  run  upon.  These 
surfaces,  in  most  cases,  consist  of  parallel  rails  of  iron, 
raised  a  little  above  the  general  level  of  the  ground,  and 
having  a  gravelled  road  between  the  rails,  so  that  the  rail- 
road combines  the  advantages  of  good  foothold  for  horses, 
where  it  is  necessary  to  use  them,  and  of  smooth,  hard, 
surfaces,  for  the  wheels  to  roll  upon.  The  wheels  are 
made  smooth  and  true,  and  guides,  or  flanges,  to  prevent 
them  from  slipping  off,  are  affixed,  either  to  the  wheels, 
or  to  the  rails, — most  commonly,  to  the  former. 

Rail-roads  are  a  modern  invention,  and  their  greatest 
improvements  have  been  made  within  the  present  century. 
In  comparing  the  effect  of  a  rail-road  with  that  of  a  com- 
mon turnpike-road,  a  saving  is  made,  according  to  Mr. 
Tredgold,*  of  seven  eighths  of  the  power  ;  one  horse  on  a 
rail-road~  producing  as  much  eftect,  as  eight  horses  on  a 
turnpike-road.  In  the  effect  produced  by  a  given  power, 
the  rail-road  is  about  a  mean  between  the  turnpike-road 
and  a  canal,  when  the  rate  is  about  three  miles  per  hour  ; 
but,  when  greater  speed  is  desirable,  the  rail-road  may 
equal  the  canal  in  effect,  and  even  greatly  surpass  it.  In 
the  Winter  season,  when  canals  are  liable  to  be  frozen, 
rail-roads,  if  kept  clear  from  snow  and  ice,  may  be  al- 
ways passable. 

In  the  construction  of  rail-roads,  it  is  desirable  that  they 
bhould  be  made  as  level  as  possible.  For  this  purpose, 
the  road  is  first  graded^  by  digging  down  the  more  ele- 

*  Treatise  on  Rail-roads  and  Carriages,  p,  3. 


EDGE   RAIL-WAT. 


25 


vated  parts,  and  raising  those  which  are  depressed.  Hills 
are  usually  passed  through  by  deep  cuts;  and,  in  some  in- 
stances, perforated  by  tunnels,  or  hollow  passages.  Val- 
hes  and  marshes  are  raised  by  embankments  of  earth,  and 
streams  are  crossed  by  wooden  bridges,  or  by  viaducts  ol 
stone,  constructed  with  arches  of  regular  masonry. 

The  earliest  rail-roads  appear  to  have  been  constructed 
of  wood  only.  But,  at  the  present  day,  iron  is  employed 
in  all  rails  from  which  durability  is  expected.  In  ^sorne 
cities,  tracks  of  hewn  stone  are  laid  for  wheels,  in  the 
streets  ;  but  these  are  seldom  executed  with  sufficient  ac- 
curacy, to  deserve  the  name  of  rail-ways.  Of  the  iron 
rail-road,  there  are  three  principal  varieties.  1.  The 
Edge  rail.     2.   The  Tram  road.     3.   The  Single  rail. 

Edge  Rail-way. — In  this  species,  which  is  now  prefer 
red  to  all  others,  and  is,  indeed,  the  only  one  now  much 
in  use,  the  rails  are  laid  with  the  edge  upward,  and  the 
carriage  is  retained  upon  them  by  a  flange,  or  projecting 
edge,  attached  to  the  wheels,  instead  of  the  rail.  These 
rails  were  originally  made  of  cast-iron,  about  three  feet 
long,  and  four  or  five  inches  deep  in  the  middle,  the  out- 
line being  curved  on  the  under  side,  to  produce  equality 
of  strength.     Fig.  9S,  represents  a  side-view  of  the  old 


Fig.  98. 


cast-iron  rail-way.  The  ends  of  the  rails  are  received  in 
a  piece  of  cast-iron,  called  a  chair,  and  these  chairs  are 
affixed  to  large  blocks  of  stone,  or  logs  of  w^ood,  called 
sleepers,  which  are  previously  placed  in  the  ground,  upon 
a  proper  level.  Fig.  99,  on  the  next  page,  is  a  section, 
or  end  view,  of  the  rail-road,  together  with  the  wheels  of  a 
carriage,  and  the  flange  which  serves  to  guide  them. 

Rails  are  now  almost  universally  made  of  wrought-iron. 
As  this  material  is  costly,  when  employed  alone,  it  is  some- 
times used  in  thin  bars,  as  a  covering  to  wooden  rails,  par- 
ticularly in  this  country,  where  timber  is  plenty,  and  iron 
II  3  XII. 


26 


ARTS  OF  LOCOMOTION. 

Fig.  99. 


expensive.*  But  the  most  common  rails  are  of  solid  iron, 
rolled  out  in  lengths  of  several  yards,  the  edges,  espec- 
ially the  upper,  being  straight,  and  thicker  than  the  other 
parts.  Wrought-iron  rails  have  the  advantage  of  being 
longer,  and,  therefore,  reducing  the  number  of  joints  ;  a 
circumstance  which  greatly  increases  the  strength,  as  well 
as  smoothness,  of  the  road. 

Mr.  Trautwine  has  published,  in  the  Frankhn  Journal, 
the  following  transverse  sections  of  eight  varieties  of  par- 
allel rails,  employed  on  different  rail-roads  in  the  United 
States.     They  are  drawn  to  a  scale  of  one  fourth  the  full 


*  The  durability  of  this  combination  of  wood  and  iron,  remains  to 
be  settled  by  longer  experience.  It  must  be  greatly  inferior  to  that  of 
iron  alone. 


TRAMS. SINGLE   RAILS.  27 

size,  and  accompanied  by  a  statement  of  the  weights,  per 
lineal  yard. 

Weights. 

No.  1.  Columbia  and  Philadelphia,  per  yard,  41i  lbs. 
a    2.  "  "  "         33     " 

"    3.   Germantown  and  Norristown,    "         39     ',' 
"    4.   Camden  and  Amboy,  "         394   '^ 

"    5.   Boston  and  Providence,  "         54     " 

"    6.   Wilmington  and  Susquehanna,   "  40     " 

"    7.   Alleghany  Portage,  "         40     '' 

"    8.   Boston  and  Providence,  "         40     " 

Tram-roads. — Tram-roads  are  flat  rails,  made  usually 
of  cast-iron,  with  an  elevated  edge,  or  flange,  on  one  side, 
to  guide  the  wheels  of  carriages  in  their  path.  Tram  rails 
are  weaker  than  edge  rails,  when  made  of  the  same 
amount  of  material,  and  it  is  sometimes  necessary  to 
strengthen  them  with  ribs  underneath.  They  are  capa- 
ble of  being  used  for  ordinary  wheel  carriages,  but  the 
introduction  of  wheels  which  are  not  perfectly  smooth,  is 
always  injurious  to  the  road.  Tram-roads  are  more  lia- 
ble to  be  covered  with  dirt,  than  rails  of  other  kinds,  and 
are  now  httle  used. 

Single  Rail. — Carriages  may  be  made  to  run  upon  a 
single  rail,  by  deviating  the  rail  from  the  ground,  and  sus- 
pending the  load  beneath  it.  In  Mr.  Palmer's  rail-way, 
the  rail  is  about  three  feet  above  the  surface  of  the 
ground,  and  is  supported  by  pillars,  placed  at  distances 
of  about  nine  feet  from  each  other.  The  carriage  con- 
sists of  two  receptacles,  or  boxes,  suspended,  one  on  each 
side  of  the  rail,  by  an  iron  frame,  and  having  two  wheels 
placed  one  before  the  other.  The  rims  of  the  wheels 
are  concave,  and  fit  the  convex  surface  of  the  rail ;  and 
the  centre  of  gravity  of  the  carriage,  whether  loaded  or 
empty,  is  so  far  below  the  upper  edge  of  the  rail,  that 
the  receptacles  hang  in  equilibrium,  and  will  bear  a  con- 
siderable inequality  of  load  without  inconvenience,  owing 
to  the  change  of  fulcrum,  allowed  by  the  breadth  of  the 
rail,  which  is  about  four  inches.  The  alleged  advantages 
of  the  single  rail  are,  that  it  is  more  free  from  lateral  fric- 
tion than  the  other  kinds  of  rail-way,  and  that,  being  high- 


28  ARTS   OF  LOCOMOTION. 

er  from  the  ground,  it  is  less  liable  to  be  covered  with 
dust  and  gravel ;  and,  lastly,  that  it  is  more  economical, 
the  construction  of  one  rail  being  less  expensive  than  of 
two.   It  has  not,  however,  been  much  introduced  into  use. 

Passings,  or  Sidings. — When  the  amount  of  travel  on 
a  rail-road  is  very  great,  it  becomes  necessary  that  the 
road  should  be  double,  one  set  of  tracks  being  provided 
for  carriages  moving  in  each  direction.  Where  there  is 
less  travel,  a  single  road  is  sufficient,  if  it  be  provided 
with  double  places,  called  sidings,  for  carriages  to  pass 
each  other,  at  convenient  distances.  The  siding,  or  pas- 
sing place,  is  a  short  length  of  additional  track,  laid  by  the 
side  of  a  line  of  rail- way,  and  connected  with  it,  at  each 
extremity,  by  suitable  curves,  the  rails  being  constructed 
and  disposed  in  such  a  manner,  that  the  carriages  can 
either  proceed  along  the  main  hne,  or  turn  into  the  sid- 
fng,  as  may  be  required. 

To  accomplish  this,  the  portion  of  rails,  forming  the 
junction  of  the  siding  with  the  main  hne,  is  made  mova- 
ble, so  as  to  join  either  track-way.  This  portion  is  term- 
ed a  switch,  and  the  points  where  one  rail  crosses  an- 
other, are  termed  crossing  points.  These  last  are  gener- 
ally fixed  or  immovable  ;  suitable  grooves  being  left,  on 
their  surface,  for  the  passage  of  the  flanges  of  the  carriage 
wheels  on  either  track-way. 

The  Turn-plate,  or  Turn-table,  is  a  contrivance  for  re- 
moving rail-way  carriages  from  one  line  of  rails  to  another. 
They  are,  generally,  made  for  crossings  at  right  angles 
with  each  other,  but  can  be  adapted  to  any  angle  that 
may  be  required.  They  consist  of  an  iron  framing,  upon 
which  iron  gratings,  or  w^ood  plankings,  are  laid,  thereby 
forming  a  table,  or  platform,  two  pairs  of  rails  being  fixed 
on  the  surface  of  the  same,  crossing  each  other  at  right 
angles.  This  platform  turns  upon  a  centre  pivot,  wiiich 
rests  upon  another  iron  frame,  set  on  masonry,  friction 
rollers  being  inserted  between  them,  at  the  extreme  edges 
of  the  table. 

Curves. — The  term  curve  is  applied  to  a  sudden  bend, 
in  a  hne  of  road,  canal,  or  rail-way.  Curves,  upon  rail- 
ways of  less  than  three  fourths  of  a  mile  radius,  should  be 


PROPELLING  POWER. LOCOMCJ I  irfiS.  29 

avoided,  as  the  centrifugal  force,  arising  upon  them,  lias  a 
tendency  to  tlTrow  the  train  off  the  rails.      They  also  pro 
duce  an  injurious  amount  of  friction,  which  wastes  pow- 
er, and  wears  the  flanges  of  the  wheels. 

When  the  rail- way  crosses  a  public  road,  it  is  made  to 
pass  at  a  lower  level  than  the  common  surface,  and  is 
protected  from  carriage  wheels,  by  an  elevated  edging  of 
wood,  or  stone  ;  bridges  are  preferred,  whenever  the  situa- 
tion permits  them  to  be  made.  Rail-ways  require  to  be 
free  from  dirt,  which  greatly  increases  the  resistance. 
Mr.  Palmer  found,  upon  a  tram-road,  that  it  required  nine- 
teen per  cent,  more  power  to  draw  the  same  carriages 
when  the  rails  were  slightly  covered  with  dust,  than  when 
they  were  swept  clean.  The  edge  rail,  however,  being 
convex  on  its  upper  surface,  retains  but  httle  dust. 

Propelling  Power. — Horses  were  originally  employed 
for  drawing  loads  upon  rail-ways,  a  horse  being  supposed 
capable  of  drawing  eight  times  as  much,  as  upon  a  com- 
mon road.  But  Locomotive  steam-engines  are  now  gen- 
erally employed  upon  rail-ways,  of  any  considerable 
length.  They  were,  at  first,  made  to  propel  carriages,  by 
means  of  a  toothed  wheel,  which  acted  upon  a  rack  at- 
tached to  one  of  the  rails  ;  but,  at  the  present  day,  they 
are  made  to  act  by  the  friction,  only,  of  the  carriage  wheels 
upon  the  plain  rail.  These  engines  are  always  made  of 
high  pressure,  since  those  of  low  pressure  are  rendered 
too  heavy,  by  the  w^eight  of  the  water  necessary  for  con- 
densation. Great  improvements  have  lately  been  made 
in  the  construction  of  locomotive  engines,  in  consequence 
of  which,  th^y  have  been  enabled  to  attain  the  extraordi- 
nary speed  of  thirty  or  forty,  and,  in  some  short  experi- 
ments, even  of  seventy,  miles,  per  hour.  (See  Steam 
Engine.)* 

Locomotive  Engines  differ  considerably  from  other 
steam-engines,  in  their  mode  of  construction  ;  and  numer 
ous  modifications  are  found  necessary,  to  render  the  ma 
chine  suitable  for  a  rapid  transit,  the  principal  of  which 
are  the  combination  of  the  engine  and  boiler  in  one,  and 
a  contrivance  for  the  rapid  generation  of  steam. 

*  Franklin  Journal,  jcix.  page  407,  New  Series. 

3* 


30  ARTS   OF  LOCOMOTION. 

It  became  necessary,  to  form  the  boiler  of  much  smaller 
dimensions,  in  proportion  to  its  power,  than  was  before 
customary,  and  to  reduce  the  size  of  the  cylinders.  A 
greater  degree  of  strength  was  also  required,  in  securing 
the  several  parts  of  the  framing  together,  in  order  to  ren- 
der the  w^hole  proof  against  the  sudden  shocks  and  strains, 
to  which  it  is  subjected. 

Locomotives  were  in  a  very  imperfect  state,  previous 
to  the  opening  of  the  Liverpool  and  Manchester  rail-way, 
having  merely  one  flue,  passing  through  the  boiler,  and 
returned  again  to  the  fire-box,  at  which  end  the  chimney 
was  situated.  A  greater  velocity  than  eight  miles  an  hour 
could  never  be  attained  by  them,  owing  to  the  small  ex- 
tent of  evaporating  surface.  They  did  not  possess  above 
one  quarter  the  power  of  the  present  locomotives. 

The  directors  of  that  rail-way,  having,  in  the  year 
1829,  offered  a  premium  of  five  hundred  pounds  for  the 
best  locomotive  engine,  the  first  stimulus  was  given  to  the 
subject.  The  Rocket  engine,  by  Mr.  G.  Stevenson,  prov- 
ed successful  in  obtaining  this  premium.  Li  the  boiler 
of  this  engine,  tubes  were  introduced,  for  the  first  time, 
which  greatly  increased  the  evaporating  powers  of  the 
engine  ;  and,  although  locomotives  have  since  been  con- 
siderably modified,  yet  this  has  formed  the  basis  of  all  the 
great  improvements,  which  have  taken  place.  A  descrip- 
tion of  it  will  be  given,  under  the  head  of  Steam  Engine. 

Mr.  Stevenson's  engine  weighed  only  four  and  a  half 
tons,  and  the  evaporating  surface  was  three  times  the  ex- 
tent of  that  in  the  former  engines,  which  weighed  up- 
wards of  seven  and  a  half  tons.  It  attaine.d  a  speed  of 
twenty-nine  miles  an  hour,  and  an  average  velocity  of  four- 
teen and  a  half  miles  an  hour.  It  was  soon  after  found, 
that,  by  constructing  engines  of  greater  size,  with  increased 
evaporating  powers,  ample  amends  would  be  made  for 
the  additional  weight.  Heavier  engines  were  introduced 
on  the  Liverpool  and  Manchester  rail-way  ;  and  the  loco- 
motives, in  general  use,  at  the  present  time,  weigh  from 
nine  to  thirteen  tons.  The  power  of  a  modern  locomo- 
tive engine,  having  tweh^e-incn  cylinders,  and  an  eighteen- 


STATIONARY  ENGINES.  31 

mch  stvoke  of  piston,  is  computed  at  about  thirty-eight  or 
forty  horse  power,  at  high  velocities,  and  seventy  or  eigh- 
ty horse  power,  at  a  slow  rate  of  speed. 

The  rapid  generation  of  steam,  in  these  locomotives, 
is  owing  to  the  great  number  of  tubes,  and  to  their  thin- 
ness, whereby  a  large  surface  of  water  receives  its  heat 
quickly,  through  a  thin  partition.  An  advantage  is  sup- 
posed to  be  derived  from  the  final  escape  of  the  steam, 
which  is  discharged  into  the  chimney. 

Various  improvements  have  been  introduced  into  the 
locomotive  engine,  one  of  which  consists  in  the  use  of 
six  wheels,  instead  of  four.  In  this  country,  many  en- 
gines are  constructed  with  six  wheels,  the  first  four  of 
which  are  united  by  their  axles,  so  as  to  form  a  kind  of 
separate  carriage,  which  is  made  to  support  one  end  of 
the  locomotive.  This  carriage  turns  on  a  central  bolt, 
like  the  fore  axle  of  a  wagon.  It  has  the  advantage, 
that  the  pressure  is  distributed  more  equally,  and  that  the 
wheels  accommodate  themselves  better,  to  curvatures  of 
the  road. 

Stationary  Engines  are  used  to  draw  up  loads  where 
the  ascent  is  too  steep  for  locomotives  to  ascend. 
Where  the  declivity  of  the  road  is  great,  loaded  carriages 
sometimes  descend,  by  their  own  gravity,  and,  at  the  same 
time,  draw  up  the  empty  ones,  by  means  of  pullies.  To 
prevent  carriages  from  acquiring  too  great  a  velocity,  in 
descending,  a  crooked  lever,  called  a  brake,  or  convoy, 
is  apphed  to  the  surface  of  the  wheels,  so  as  to  retard 
them  by  its  friction.*  When  loaded  carriages  are  trans- 
ferred from  one  part  of  the  road  to  another,  of  greater 
elevation,  they  are  either  drawn  up  an  inchned  plane,  with 
ropes,  by  horses,  or  stationary  engines  ;  or,  in  some  cases, 
they  may  be  lifted  perpendicularly,  by  pullies.  This  meth- 
od, however,  is  seldom  practised. 

*  A  retarding  friction  is  produced,  when  necessary,  in  mountaincus 
countries,  upon  common  roads,  by  chaining  one  of  the  wheels,  when 
the  carriage  goes  down  hill,  so  as  to  prevent  its  turning.  The  same 
effect  is  produced, in  a  safer  manner,  by  placing  a  wooden  shoe,  like  a 
runner,  under  one  of  the  wheels. 


32  ARTS  OF  LOCOMOTION. 


CANALS. 

Canals  are  artificial  channels  for  water,  cut  for  the  pur-" 
pose  of  admitting  inland  navigation.  The  great  utility  of 
canals,  in  facilitating  transportation,  has  caused  them  to  be 
constructed  in  all  ages.  The  canals  of  the  ancients  were 
chiefly  made  on  one  level,  so  as  to  form  merely  artificial 
rivers,  or  creeks.  Those  of  the  moderns,  by  means  of 
locks,  are  carried,  indiscriminately,  over  ground  which  is 
depressed,  or  elevated.  In  level  tracts  of  country,  if  the 
earth  is  of  suitable  character,  canals  are  easily  made. 
But,  in  loose  and  crumbling  soils,  in  undulating,  rocky, 
and  mountainous,  tracts,  and  in  those  which  are  intersected 
by  large  streams,  their  construction  becomes  expensive 
and  difficult.  To  surmount  these  difficulties,  loose  soils 
are  defended  with  firmer  materials,  vallies  are  passed  by 
embankments,  hills  are  penetrated  by  deep  cuttings  or 
tunnels,  rivers  are  crossed  with  aqueducts,  and  declivities 
are  ascended  and  descended  by  locks.  In  order  that  wa- 
ter may  not  be  wanting  in  any  part  of  the  canal,  a  supply 
is  ensured  at  the  highest  level,  and  this  gradually  passes 
off  through  the  locks,  to  the  lowest.  The  streams  v.-hich 
furnish  the  water  at  this,  and  other,  points,  are  called 
feeders. 

Embankments. — Canals  are  dug  with  sloping  sides,  to 
prevent  the  banks  from  caving  in.  The  boats  being,  in 
almost  all  cases,  drawn  by  horses,  a  firm,  uninterrupted, 
towing  path  is  formed  on  one  of  the  banks.  The  banks 
are  hable,  in  time,  to  become  indented  and  washed  away, 
by  the  constant  agitation  of  the  water,  occasioned  by  the 
passage  of  boats.  To  prevent  this,  they  are  sometimes 
secured,  by  driving  close  rows  of  stakes  against  the  banks  ; 
but,  the  only  effectual  protection  is  found  in  waUing  the 
banks  with  stone.  When  the  canal  crosses  a  section  of 
country,  the  surface  of  which  is  lower  than  the  intended 
surface  of  the  water,  the  canal  is  raised  to  the  proper 
level,  by  means  of  embankments.  These  are  artificial 
baaks,  or  dykes,  made  of  such  materials  as  will  not  be 
liable  to  leak,  and  of  such  form  and  strength,  that  they 
will  not  be  broken  by  the  pressure  of  the  water.     The 


AQUEDUCTS. TUNNELS.  33 

surface  of  these  banks  is  of  a  sloping  form,  and  is  secured 
by  sodding,  and,  in  some  instances,  by  piles,  or  stone 
walls.  Where  the  nature  of  the  earth  renders  leakage 
probable,  it  is  common  to  cover  the  bottom  and  sides  of 
the  canal  with  a  lining  of  puddle,  which  is  formed  from 
loam,  or  clay,  and  gravel,  worked  up  with  water.  For 
additional  security,  a  trench  is  dug,  in  each  bank,  to  a 
greater  depth  than  the  bottom  of  the  canal,  and  filled  with 
puddle. 

It  sometimes  happens,  that  the  embankments  act  as  a 
dam,  to  prevent  the  land,  on  one  side  of  the  canal,  from 
being  properly  drained.  In  this  case,  culverts,  or  sub- 
terranean passages,  are  constructed  underneath  the  canal, 
but  not  communicating  with  it,  to  effect  the  necessary 
draining.  Culverts  are  made  of  brick,  or  stone,  and  re- 
quire to  be  strong  and  tight. 

Aqueducts. — When  a  canal  crosses  a  river,  or  a  deep 
ravine,  it  is  supported,  at  the  proper  level,  by  an  aqueduct. 
This  structure  resembles  a  stone  bridge,  formed  of  strong 
piers  and  arches,  of  regular  masonry,  rendered  as  tight  as 
possible,  with  hydraulic  cement.  Upon  the  top,  a  level 
channel  for  the  water  is  formed.  This  is  secured  with 
strong  and  tight  walls,  on  the  sides,  and  lined  within  by  a 
coating  of  clay.  Room  for  the  towing  path  must  be  preserv- 
ed, on  one  of  the  sides.  In  England,  aqueducts  have 
sometimes  been  made  of  casViron. 

Tunnels. —  Tunnels  are  subterranean  passages,  most 
frequently  cut  through  the  base  of  hills,  to  afford  a  level 
water-course  for  canals.  Tunnels  are  also  made  for  the 
passage  of  rail-ways,  and,  in  some  cases,  of  highway-roads. 
When  they  are  obHged  to  be  cut  through  solid  rock,  which 
is  done  chiefly  by  blasting,  their  formation  is  difficult  ; 
but  they  require  no  artificial  security  for  their  subsequent 
protection.  But  tunnels,  which  are  made  in  soft  earth,  re- 
quire to  be  arched  over,  for  their  whole  length,  with  stone, 
or  brick  ;  and,  in  loose,  springy  ground,  the  bottom,  like- 
wise, must  be  defended  with  an  inverted  arch.  That  tun- 
nels may  be  properly  ventilated,  especially  while  digging, 
shafts,  or  vertical  passages,  are  sunk,  at  proper  distances, 
in  which  fires  are  kept  burning,  to  create  a  current  for  dis- 


34  ARTS   OF  LOCOMOTION. 

charging  the  foul  air.  One  of  the  most  remarkable  tun- 
nels is  that  at  Worsley,  on  the  Duke  of  Bridgewater's 
canal,  which,  with  all  its  branches,  is  estimated  at  eigh- 
teen miles  in  length. 

Gates  and  Weirs. — As,  all  canals  are  liable  to  have 
their  banks  broken  through,  during  violent  rains  and  fresh- 
ets, it  is  important  to  lessen  the  injury,  which  results  from 
such  accidents,  by  retaining  as  much  of  the  water  in  the 
canal  as  possible.  To  effect  this  object,  safety-gates  and 
stop-gates  are  placed,  at  suhable  distances  from  each  other, 
on  the  canal,  so  that,  by  closing  them,  at  any  time,  in  case 
of  accident,  the  escape  of  that  part  of  the  water,  which  is 
beyond  them,  may  be  prevented.  These  gates  are  some- 
times attached  to  the  sides,  and  sometimes  lie  upon  the 
bottom. 

Certain  parts  of  the  banks,  called  Weirs,  are  made  lower 
than  the  rest,  to  discharge  the  superfluous  water,  and  keep 
the  surface  at  a  proper  level.  To  prevent  them  from 
being  gullied,  or  worn  away,  by  the  attrition  of  the  water, 
they  are  commonly  made  of  stone,  or,  sometimes,  of  wood. 

Locks. — When  a  canal  changes  from  one  level  to  an- 
other, of  different  elevation,  the  place,  where  the  change 
of  level  occurs,  is  commanded  by  a  Lock.  Locks  are 
tight,  oblong  enclosures,  in  the  bed  of  the  canal,  fur- 
nished with  gates,  at  each  end,  which  separate  the  higher, 
from  the  lower,  parts  of  the  canal.  When  a  boat  passes 
up  the  canal,  the  lower  gates  are  opened,  and  the  boat 
glides  into  the  lock  ;  after  which,  the  lower  gates  are  shut. 
A  sluice,  communicating  with  the  upper  part  of  the  canal, 
is  then  opened,  and  the  lock  rapidly  fills  with  water,  ele- 
vating the  boat  on  its  surface.  When  the  lock  is  filled  to 
the  highest  water  level,  the  upper  gates  are  opened,  and 
the  boat,  being  now  on  the  level  of  the  upper  part  of  the 
canal,  passes  on  its  way.  The  reverse  of  this  process  is 
performed,  when  the  boat  is  descending  the  canal. 

Locks  are  made  of  stone,  or  brick,  and,  sometimes,  ol 
wood.  The  walls  are  sometimes  erected  upon  an  inverted 
arch,  and  also  upon  piles,  if  the  soil  is  alluvial,  or  loose. 
They  are  laid  with  hydraulic  cement,  and  rendered  im- 
pervious to  water.     The  gates  are  commonly  double,  re- 


LOCKlS.  35 

sembling  folding  doors,  turning  upon  coin-posts ^  which  are 
next  the  walls.  They  meet  each  other,  in  most  instances, 
at  an  obtuse  angle,  and  the  pressure  of  the  water  serves  to 
keep  their  contact  more  firm.  The  hydrostatic  pressure, 
in  these  cases,  being  in  full  force,  in  a  direction  perpendic- 
ular to  the  surface  of  the  gates,  has  a  different  action  from 
that  of  the  pressure  of  gravity,  appHed  to  a  roof,  or  simi- 
la.r  structure,  and  gives  to  long  gates  a  greater  compara- 
tive disadvantage  than  to  short  ones.  Cast-iron  gates  are 
sometimes  used,  in  England,  curved  in  the  form  of  a  hori- 
zontal arch,  with  their  convex  side  opposed  to  the  water. 
Valves  are  small  sliding  shutters,  which  admit  a  stream  of 
water,  for  the  purpose  of  gradually  filling,  or  emptying,  the 
lock,  to  prevent  the  shock  of  suddenly  opening  the  gates. 

In  situations,  where  there  is  a  scarcity  of  water,  the 
waste,  occasioned  by  frequently  opening  the  gates,  for  the 
passage  of  boats,  is  too  great  for  the  amount  supplied  to 
the  canal.  In  these  cases,  to  economize  the  water,  re- 
servoirs are  provided,  at  different  heights,  on  each  side  of 
the  lock.  The  water,  in  the  upper  parts  of  the  lock,  is 
discharged  nito  these  reservoirs,  and  only  that  in  the  lower 
parts  is  suffered  to  escape  into  the  lower  canal.  After- 
wards, the  water  in  these  reservoirs  is  used  to  fill  again  the 
lower  parts  of  the  lock,  and  thus,  the  same  w^ater  is  made 
use  of,  a  second  time. 

In  China,  where  inland  navigation  is  much  practised, 
it  is  said  there  are  no  locks,  but  boats  are  transferred, 
from  one  level  to  another,  by  means  of  inclined  planes. 
This  method  is  sometimes  practised,  in  Europe,  and  it  had 
a  zealous  advocate  in  the  late  Mr.  Fulton.  To  effect  this 
transfer  most  advantageously,  two  boats,  passing  in  oppo- 
site directions,  are  connected  together  by  a  chain,  passing 
over  a  pulley.  One  boat,  in  descending  the  plane,  assists, 
by  its  weight,  to  draw  the  other  upward.  Sometimes, 
instead  of  inclined  planes,  perpendicular  lifts  have  been 
proposed,  by  which  the  boats  are  hoisted  directly,  by  pul- 
lies,  from  one  level  to  another,  or  lowered,  in  the  opposite 
direction,  by  the  same  means.  The  objection  to  all  these 
modes  exists  in  the  strain,  to  which  the  boats  are  exposed, 
unsupported  by  the  pressure  of  the  water.     Various  ex- 


36  ARTS   OF  LOCOMOTION. 

pedients  have  been  proposed,  for  altering  the  level  oi  the 
water,  and  transferring  boats,  by  means  of  large  plungers, 
diving  chests,  &c.;  but  none  oi  uiem,  as  yet,  appear  to 
have  been  approved  in  practice.* 

Fig.  100. 


Boats. — Canal  boats  are  made  narrow,  for  passing  each 
other,  and  draw  water  proportioned  to  the  depth  of  the 
canal.  Their  length  is  limited  only  by  that  of  the  locks. 
They  are  drawn  by  horses,  on  the  tow-path,  being  kept, 
by  the  rudder,  from  coming  in  contact  with  the  bank.  No 
species  of  oars,  poles,  or  paddle-wheels,  is  allowed,  on 
account  of  the  injury  done  to  the  bottoms  and  banks,  by 
their  use.  It  is  said,  however,  that  the  steam-engine  has, 
in  some  cases,  been  used,  without  injury  to  the  canal,  by 
causing  the  paddle-wheels  to  work  in  a  water  passage,  or 
casing,  which  passes  through  the  boat,  above  its  bottom. 

Size  of  Canals. — Canals  differ  greatly  from  each  other, 
not  only  in  their  length,  but  their  size,  and  the  draught  of 
water  which  they  admit.  One  of  the  largest  canals,  as 
far  as  the  volume  of  water  is  concerned,  is  the  great 
Dutch  canal,  which  connects  the  city  of  Amsterdam  with 
the  Helder,  on  the  north  coast  of  Holland.  This  canal 
is  fifty  miles  in  length,  one  hundred  and  twenty-four  feet 
in  width,  at  the  surface  of  the  water,  thirty-six  feet  wide, 
at  bottom,  and  about  twenty-one  feet  deep.  It  is  large 
enough  to  permit  one  frigate  to  pass  another.  '  The  Cal- 
edonian canal  extends  from  the  Murray  Frith,  on  the 
eastern  coast  of  Scodand,  to  Loch  Eil,  on  the  western, 
and  admits  of  the  passage  of  large  ships.  It  is  one  hun- 
dred and  twenty  feet  wide,  at  the  water  surface,  and  fifty 
wide,  at  bottom.  The  depth  of  water  is  twenty  feet. 
The  distance,  from  sea  to  sea,  is  about  fifty-nine  miles, 
of  which  thirty-seven  and  a  half  is  lake  navigation,  and 

*  Repertory  of  Arts,  vols.  i.  ii.  and  xxiii. 


SAILING. FORM   OF  A   SHIP.  37 

twenty-one  and  a  half  is  cut.*  The  canal  of  Languedoc, 
in  France,  is  sixty-four  leagues  in  length,  and  connects 
the  Atlantic  ocean  with  the  Mediterranean  sea.  It  is 
sixty-four  feet  wide,  at  the  surface,  and  navigable  for  ves- 
sels of  one  hundred  tons.  The  great  New  York,  or  Erie, 
canal  is  three  hundred  and  sixty  miles  long,  and  extends 
from  the  Hudson  river,  at  Albany,  to  Lake  Erie,  at 
Buffalo.  It  is  forty  feet  wide,  at  the  surface,  twenty-eight 
feet  wide,  at  bottom,  and  has  four  feet  depth  of  water. 

SAILING. 

Form  of  a  Ship. — The  movement  of  bodies  through 
water,  if  performed  within  certain  hmits  of  velocity,  is  at- 
tended with  less  resistance  than  that  which  takes  place  in 
most  other  modes  of  transportation.  A  body,  however, 
of  given  size,  will  encounter  a  greater  or  less  resistance 
from  the  water,  according  to  its  proportions,  and  the  sort 
of  surface  which  it  opposes  to  the  fluid.  In  calculating 
the  proper  form  for  a  ship,  it  is  necessary  to  consider  the 
kinds  of  pressure,  to  which  bodies,  moving  in  fluids,  are* 
subject.  If  we  suppose  an  oblong  square  box,  or  paral- 
lelopiped,  as  ABCD,  in  Fig.  101,  to  move  through  the 

Fig.  101. 


C  I? 

water,  in  the  direction  of  its  length,  the  pressure  will  be 
increased  before,  and  diminished  behind  it,  the  surface 
of  the  water  being  elevated,  at  the  anterior  extremity,  and 
depressed,  at  the  posterior  ;  an  efiect  which  increases,  in 
a  high  ratio,  as  the  velocity  becomes  greater.  The  prin- 
cipal part  of  the  water,  which  is  before  the  moving  body, 
divides  and  passes  off  by  the  sides  ;  but  a  certain  quantity 
of  what  is  called  dead  water  is  pushed  along,  in  advance  of 
the  moving  body,  nearly  in  the  same  manner  as  if  it  were 

*  Supplement  to  the  Encyclopedia  Britannica,  and  Edinburgh  Ency- 
clopedia. 

II.  4  XII. 


38  ARTS   OF  LOCOMOTION. 

a  part  of  ihe  body  itself.  The  shape  of  this  dead  water, 
at  the  surface,  is  found  to  be  that  of  an  irregular  triangle, 
and  hence  it  becomes  advantageous  to  add  to  the  moving 
body  an  extremity,  or  boic^  having  nearly  the  same  shape 
as  the  dead  water,  and  occupying  its  place,  as  in  the  dot- 
ted line,  BED.  On  the  other  hand,  there  occurs,  behind 
the  moving  body,  a  depression  of  surface,  and  a  partially 
empty  space,  which  is  also  of  a  triangular,  or  wedge,  form, 
consisting  of  the  room  which  the  moving  body  has  just  left, 
and  into  which  the  water,  upon  each  side,  has  not  yet  flow- 
ed. The  cavity,  which  is  thus  formed,  resists  the  progress 
of  the  body,  by  its  negative  pressure.  Its  effect  is  readily 
understood,  when  we  consider,  that,  if  the  water  before  the 
moving  body  be  raised  one  foot,  while  the  water  behind 
it  is  depressed  one  foot,  the  difference  of  pressure,  upon 
the  two  extremities,  will  be  equal  to  that  resulting  from  two 
feet.  On  this  account,  it  is  advantageous  to  add  to  the 
moving  body  a  tapering,  or  wedge-shaped,  extremity,  be- 
hind, capable  of  occupying  this  cavity,  and  nearly  answer- 
ng  to  it  in  shape,  as  represented  by  the  dotted  line,  AGO. 
The  consequence  will  be,  that  the  water,  which  is  advanc 
ing  from  both  sides  to  fill  up  the  vacuity,  will  meet  the  ta 
pering  sides  of  the  vessel  soon  enough  to  obviate,  or  great- 
ly diminish,  the  negative  pressm^e.  The  form,  produced  by 
this  general  outline,  varied  by  a  proper  curvature  of  the 
sides  and  bottom,  corresponds  nearly  to  that  which  is  adop- 
ted in  the  construction  of  ships,  and  also  to  that  pur- 
sued by  Nature,  in  the  structure  of  fishes.  If  a  vessel  be 
intended  for  a  fast  sailer,  its  proportionate  length,  and  its 
sharpness,  before  and  behind,  must  be  increased,  since 
both  the  positive  and  negative  pressure,  and  the  extent  of 
the  dead  water  and  vacant  space,  will  increase  with  the 
velocity. 

Keel  and  Rudder. — The  use  of  the  keel,  which  is  a 
projecting  timber,  extending  the  whole  length  of  the  ship's 
bottom,  is  to  assist  in  confining  the  motion  of  the  ship  to 
its  proper  direction,  and,  by  its  lateral  resistance,  to  dimin- 
ish the  disposition  to  roll,  or  vibrate,  from  side  to  side. 
The  rudder,  which  is  a  perpendicular  part  attached,  by 
braces,  resembhng  hinges,  to  the  stern-post  of  the  vessel. 


EFFECT   OP   THE    WIND.  39 

serves  to  govern  the  ship's  course,  by  altering  the  relative 
resistance  of  its  two  sides.  Thus,  while  the  ship  is  under 
way,  if  the  rudder  is  turned  to  one  side,  it  receives  an 
impulse  from  the  water  on  that  side,  causing  the  stern  to 
turn  tow^ards  the  opposite  side,  where  no  such  resistance 
exists,  thus  altering  the  directit)n  of  the  keel,  and  the 
general  course  of  the  vessel. 

Effect  of  the  Wind. — When  a  ship  sails  in  the  same 
direction  as  the  wind,  she  is  said  to  he. scudding,  or  sail- 
ing before  the  wind,  and  if  she  had  but  one  sail,  it  would 
act  with  the  greatest  advantage,  when  perpendicular,  or 
nearly  so,  to  the  wind. 

When  a  ship  advances  against  the  wind,  and  endeavors 
to  proceed,  in  the  nearest  direction  possible,  to  the  point 
of  compass  from  which  the  wind  blows,  she  is  said  to  be 
close-hauled.  A  large  ship  will  sail  against  the  wind  with 
her  keel  at  an  angle  of  six  points  with  the  direction  of  the 
wind,  and  sloops,  and  smaller  vessels,  may  sail  much  near 
er.  When  a  ship  is  neither  sailing  before  the  wind,  nor 
close-hauled,  she  is  said  to  be  sailing  large.  In  this 
case,  her  sails  are  set  in  an  obHque  position,  between  the 
direction  of  the  wind,  and  that  of  the  intended  course  ;  as 
represented  in  the  various  plans  of  vessels  in  Fig.  102, 
on  page  40,  where  the  direction  of  the  wind  is  represented 
by  the  arrow,  and  the  position  of  the  yards  and  sails,  which 
is  necessary  for^proceeding  on  the  various  points  of  com- 
pass, is  shown  by  the  transverse  lines  on  each  plan.  The 
relation  of  the  wind  to  the  course  of  the  vessel  is  deter- 
mined by  the  number  of  points  of  the  compass,  between 
the  course  she  is  steering,  and  the  course  which  she  w^ould 
be  steering,  if  close-hauled.  In  Fig.  102,  the  ships,  [a 
and  6,]  are  close-hauled,  and  the  ships,  [c  and  c?,]  the  for- 
mer steering  east  by  north,  and  the  latter  west  by  north, 
have  the  wind  one  point  large.  The  ships,  [e  and  /,] 
one  steering  east,  and  the  other  west,  have  the  wind  two 
points  large.  In  this  case,  the  wind  is  at  right  angles 
with  the  keel,  and  is  said  to  be  upon  the  beam.  The 
ships,  [g  and  /i,]  steering  southeast,  and  southwest,  have 
the  wind  six  points  large,  or,  as  it  is  commonly  termed, 
upon  the  quarter,  and  this  is  considered  as  a  very  favora- 


40 


ARTS   OF  LOCOMOTION. 

Fig.  102. 


ble  manner  of  sailing,  because  all  the  sails  cooperate  to 
increase  the  ship's  velocity  ;  whereas,  Vhen  the  wind  is 
directly  aft,  as  in  the  vessel,  [m,]  it  is  partly  intercepted  by 
the  after  sails,  and  prevented  from  striking,  with  its  full 
force,  on  those  which  are  forward.  The  force  of  a  wind 
which  strikes  obliquely  upon  the  sails,  supposing  them 
flat  surfaces,  is  resolvable  into  two  forces,  one  of  which 
tends  to  push  the  vessel  ahead,  and  the  other  to  push 
her  sideways.  If  the  form  of  the  vessel,  instead  of  being 
oblong,  were  circular,  like  a  tub,  she  would  move  in  the 
direction  of  the  diagonal  of  a  rectangle,  representing  these 
two  forces,  and  her  course  would  be  at  right  angles  with 
the  position  of  the  sail,  or  in  the  direction  of  the  line  AB, 
in  Fig.  103.  But,  owing  to  the  oblong  shape  of  the  vessel, 
and  the  influence  of  her  keel,  it  requires  about  twelve 


STABILITY  OF  A  SHIP.  41 

times  as  much  force  to  pusn  her  sideways,  as  to  push  her 
head  foremost.*  The  obhque  impulse,  therefore,  will 
carry  her  a  great  distance  forward,  in  the  time  that  she  is 
drifting  a  short  distance  to  the  leeward,  and  it  is  this  re- 
lative difference  of  progress,  which  enables  a  vessel  to 
advance,  even  against  the  wind.  The  angular  deviation 
of  a  ship's  real  course,  from  her  apparent  course,  upon 
which  her  head  is  directed,  is  called  the  leeway.  In  the 
vessel,  [Fig.  103,]  with  the  wind  blowing  in  the  direction 


of  the  arrows,  and  the  sails  set  as  represented,  if  the  ves- 
sel were  moving  in  a  rail-way,  or  unchangeable  channel, 
her  course  would  be  BD  ;  but,  in  the  water,  she  drifts  so 
much  to  the  leeward,  that  her  real  course  is  BC,  and  the 
angle,  CBD,  represents  the  amount  of  leeway. 

Stability  of  a  Ship. — The  masts  of  a  ship,  when  acted 
upon  by  the  pressure  of  the  wind  against  the  sails,  are  so 
many  levers,  tha  tendency  of  which  is,  to  overset  her. 
To  counteract  this  tendency,  a  sufficient  weight  of  ballast, 
or  cargo,  is  stowed  in  the  bottom  of  the  hold,  to  carry 
the  centre  of  gravity  into  the  lower  part  of  the  hull,  so 
that  this  part  will  always  preponderate,  while  the  relative 
buoyancy  of  the  upper  part  causes  the  vessel  to  right,  as 
often  as  her  position  is  disturbed.  If  the  ballast  is  too 
light,  or  is  stowed  too  high  in  the  hold,  the  vessel  is  said 
to  be  too  cranky  and  rolls  more,  and  cannot  carry  so 
much  sail,  without  danger  of  oversetting.  On  the  other 
hand,  if  the  ballast  is  too  heavy,  and  placed  too  low,  the 
vessel  is  said  to  be  too  stiff,  and  not  only  draws  so  much 
water  as  to  impede  her  velocity,  but  is  liable  to  have 

♦  Robinson's  Mechanhal  Philosophy,  vol.  iv.  p.  620. 
4* 


42  ARTS   OF  LOCOMOTION. 

her  masts  endangered,  by  the  shocks  which  result  from 
the  suddenness  of  her  motions.  In  regard  to  shape,  an 
increase  of  the  width  of  a  shi{)  increases  her  stabihty,  but, 
at  the  same  time,  detracts  from  her  power  as  a  fast  sailer. 

Steam  Boats. — Experiments  on  the  propulsion  of  ves- 
sels, by  steam,  were  made  in  Europe,  and  this  country, 
at  different  times,  during  the  last  century;  but  the  first 
successful  introduction  of  steam  navigation,  on  a  large 
scale,  was  made  in  America,  by  the  late  Mr.  Fulton, 
about  the  year  1807.  The  application  of  the  steam-en- 
gine to  navigation,  has  given  to  vessels  the  advantage  of 
greater  speed  and  regularity,  in  the  performance  of  their 
passages,  without  interruption  from  the  ciiangeable,  and 
often  adverse,  operation  of  the  elements.  In  the  action 
of  the  steam-engine,  as  in  that  of  rowing,  a  vessel  is  pro- 
pelled by  a  succession  of  impulses,  which  act  against  the 
inertia  of  the  water. 

A  power  acting  within  a  boat,  whether  of  men,  of 
horses,  or  of  steam,  may  be  applied  to  the  water,  in  va- 
rious ways.  Some  of  the  principal  of  these  are  the  fol- 
lowing. 1.  A  system  of  oars,  or  paddles,  has  been 
made  to  act  with  alternating  strokes,  rising  out  of  water 
at  the  end  of  each  stroke.  2.  An  alternating  paddle 
has  been  contrived,  w4iich  is  continually  immersed,  and 
which  folds  up,  like  the  foot  of  a  w^ater-fowd,  during  the 
backward  stroke.  3.  It  has  been  pr(^osed  to  drive  a 
current  of  air,  or  a  current  of  water,  out  at  the  stern  of 
the  vessel.  4.  Spiral  wheels  and  water-screws,  or 
wheels  with  oblique  vanes,  hke  those  of  a  windmfll,  have 
been  made  to  turn  under  water,  with  their  axes  parallel 
to  the  keel  of  the  vessel.  5.  Obhque  planes,  acting  with 
an  alternate,  instead  of  a  revolving,  stroke,  were  recom- 
mended by  Bernoulli.  6.  Paddle-wheels.  These,  from 
their  simplicity,  and  advantageous  mode  of  action,  have,  in 
common  use,  superseded  all  the  rest.  They  consist  of 
paddles,  or  float-boards,  attached  to  the  arms,  or  spokes, 
of  a  wheel,  the  axis  of  which  is  at  right  angles  with  the 
keel.  Their  common  place  is  on  the  sides  of  the  boat, 
as  in  Fig.  104,  on  the  opposite  page. 

The  outline  of  the  float-boards,  or  paddles,  is  com- 


STEAM-BOATS. 
Fig.  104. 


43 


monly  rectangular,  though  ^Ir.  Tredgold  recommends  that 
'heir  outer  extremity  should  be  parabolic.  The  best  po- 
sition for  the  paddles  is  in  a  plane,  passing  through  the  axis 
of  the  wheels  ;  but  with  this  position,  they  strike  the  water 
obliquely,  in  entering,  and  lift  a  considerable  quantity,  on 
quitting  it ;  both  of  which  motions  occasion  loss  of  pow- 
er. Attempts  have  been  made  to  correct  this  disadvant- 
age, by  various  mechanical  arrangements,  in  which  the 
paddles  are  made  to  enter  and  leave  the  water  perpen- 
dicularly ;  but  want  of  simplicity,  and  objections  of  vari- 
ous other  kinds,  have  prevented  them  from  coming  into 
use.  It  has  be"en  proposed  to  fix  a  series  of  paddles  up- 
on longitudinal  chains,  passing  round  wheels,  and  parallel 
to  each  side  of  the  vessel.  By  this  mode,  a  number  of 
perpendicular  paddles  would  act  upon  the  water  at  once  ; 
but  it  will  be  seen,  that,  as  no  more  of  these  paddles  can 
operate  usefully,  than  are  sufficient  to  put  the  water  be- 
tween.them  into  motion,  a  part  of  the  series  will  be  less 
useful,  than  if  it  acted  upon  water  at  rest.  In  wheels  of 
the  common  form,  it  is  advantageous  to  have  a  double 
row  of  paddles,  one  outside  the  other,  and  so  placed,  that 
the  paddles  of  one  series  shall  be  opposite  the  intervals 
of  the  other,  and  thus  enter  the  water  successively,  and  in 
different  places.*  This  plan  is  the  one  most  generally 
adopted,  in  American  steam-boats.  In  Perkins's  propel- 
ling wheel,  the  paddles  are  placed  obliquely,  in  regard  to 
the  axis  of  the  wheel,  and  the  w^heel  itself  is  placed  ob- 

*  For  examinations  of  the  different  propelling  powers,  see  the  Edin- 
burgh Encyclopedia,  article  '  Navigation  Inland,'  ascribed  to  Mr.  Tel 
"ord  ;  also,  Tredgold  on  the  Steam  Engine,  p.  309. 


44  ARTS   OF  LOCOMOTION. 

liquely,  in  regard  to  the  keel  of  tb»-boat.      This  arrange 
ment  is  such,  that  the  paddles  enter  and  leave  the  water 
obliquely,  but,  at  the  time  of  their  greatest  immersion,  they 
are  at  right  angles  with  the  keel,  and  in  the  most  favora- 
ble position  for  propelling  the  boat. 

The  average  speed  of  a  well-constructed  steam -boat 
has  been  assumed  at  fourteen  miles  per  hour,  and  the 
greatest  speed  at  sixteen  miles.* 

Steam-boats  have  been  considered  as  best  adapted  to 
the  navigation  of  rivers,  and  straits,  or  sounds,  where  the 
water  is  comparatively  smooth.  In  the  open  sea,  the  vio- 
lence of  the  waves  renders  the  action  of  the  paddle-wheels 
irregular,  and  it  was,  for  a  long  time,  thought  difficult  for 
them  to  carry  fuel  sufficient  to  supply  the  engine,  during 
long  voyages.  The  steam-ship  Savannah  first  crossed 
the  Atlantic,  in  1819,  and  was  twenty-one  days,  from  land 

*  Mr.  W.  S.  Redfield,  of  New  York,  has  addressed  to  Lieutenant  Hos- 
ken,  the  commander  of  the  Great  Western  steam-ship,  a  letter,  in  which 
he  says  :  "  Tiiere  is,  if  T  mistake  not,  some  misapprehension  prevail 
ing,  both  in  England  and  America,  in  regard  to  the  ordinary,  as  well  as 
maximum,  speed  of  the  best  steam-vessels.  This  is  mainly  to  be  as 
cribed  to  three  causes  :  1st.  The  erroneous  statements  which  often  find 
their  way  into  newspapers.  2d.  To  a  mistaken  estimate  of  the  velo- 
city of  the  tides  and  currents.  And,  3d,  to  the  erroneous  popular  esti- 
mate of  navigating  distances,  which,  on  nearly  all  internal,  or  coasting, 
routes,  in  both  countries,  so  far  as  my  knowledge  extends,  are  habitu- 
ally overrated.  This  may  explain,  on  one  hand,  the  extravagant  claims 
to  velocity,  which  are  sometimes  stated  of  American  steam-boats  ;  and, 
on  the  other  hand,  may  account  for  the  strange  incredulity,  which  has 
been  manifested  by  Dr.  Lardner,  and  others,  not  well  acquainted  with 
the  structure  and  performances  of  American  steam-boats.  The  ac- 
quaintance which  I  have  had  with  the  navigation  of  the  Hudson,  by 
steam,  during  the  last  thirteen  years,  enables  me  to  speak  with  confi- 
dence on  some  of  the  points  involved. 

"  The  usual  working  speed  of  the  best  class  of  steam-boats,  on  the 
Hudson,  may  be  estimated  at  fourteen  statute  miles  per  hour,  through 
still  water  of  good  depth.  That  they  are  not  unfrequently  run  at  a 
lower  speed,  is  freely  admitted.  But  the  maximum  speed  of  these 
boats  is,  and  has  been,  for  several  years,  equal  to  about  sixteen  miles 
per  hour.  In  regard  to  the  "  admitted  four  miles  per  hour  tide  up  the 
Hudson,"  the  admission  is  extremely  erroneous.  The  average  advan- 
tage to  be  realized,  in  a  passage  on  flood-tide,  from  New  York  to  Al- 
bany, is  not  more  than  one  mile  and  a  half  per  hour,  or,  at  the  most, 
say  twelve  miles,  in  a  passage  to  Albany, — equal  to  about  one  twelfth 
of  the  distance,  as  performed  under  the  most  favorable  circumstances  " 


STEAM-SHIPS. DIVING-BELL,  45 

to  land,  during  eighteen  of  which,  only,  she  was  able  to 
use  her  engine. 

Steam  Ships. — The  difficulties  attendant  on  marine 
steam  navigation,  which,  but  a  short  time  ago,  were  pro- 
nounced, by  some  distinguished  authorities,  to  be  insur- 
mountable, have  been  completely  overcome  by  the  intro- 
duction, in  1838,  of  steam-ships  of  extraordinary  size, 
propelled  by  engines  of  great  power.  The  Great  West- 
ern, which  arrived  at  New  York,  from  Bristol,  in  April, 
1838,  measured,  for  her  extreme  length,  two  hundred  and 
thirty-six  feet,  and  in  width,  between  the  outside  of  the 
paddle-cases,  fifty-eight  feet.  The  British  Queen,  which 
followed  in  the  next  year,  is  two  hundred  and  seventy- 
five  feet  long,  which  is  stated  to  be  thirty-five  feet  longer 
than  any  ship  in  the  British  navy.  She  has  two  engines, 
of  two  hundred  and  fifty  horse  power  each.  It  is  now 
settled,  that  the  passage  of  the  Atlantic  may  be  made, 
safely  and  successfully,  by  vessels  of  this  size,  and  ac- 
complished, under  favorable  circumstances,  in  less  than  a 
fortnight. 

The  success  attending  these  experiments  has  led  to 
the  multiplication  of  ocean-steamers,  which  are  intended 
to  ply  upon  all  the  great  tracks  of  commerce,  in  the  civil- 
ized world.  'The  communication  between  Europe  and 
the  United  States,  as  well  as  that  with  the  West  and  East 
Indies,  and,  indeed,  with  most  of  the  important  sea-ports 
on  the  globe,  may  be  considered  as  hereafter  to  be  per- 
formed, in  half  the  time  which  was  formerly  required,  and 
with  far  greater  certainty,  in  regard  to  the  times  of  arrival 
and  departure. 

Of  the  numerous  steam-ships  now  building,  or  built,  in 
Great  Britain,  to  ply  between  that  country  and  foreign 
ports,  some  are  constructed  entirely  of  iron.  Some  are 
of  immense  size,  exceeding  that  of  the  British  Queen, 
which  has  already  been  mentioned. 

DIVING-BELL. 

The  diving-bell  is  an  inverted  vessel,  containing  air^ 
and  used  for  the  purpose  of  enabling  persons  to  descend, 
with  safety,  to  great  depths  uuder  water.    It  is  made  tight 


46  ARTS   OF  LOCOMOTION. 

at  the  top  and  sides,  but  is  entirely  open  at  bottom.  Its 
principle  is  the  same  with  that  ot"  a  gasometer,  and  may 
be  familiarly  illustrated,  by  immersing  an  inverted  tumbler 
in  a  vessel  of  water.  The  air  cannot  escape  from  the  in- 
side of  the  vessel,  being  necessitated,  by  the  order  of  spe- 
cific gravities,  to  occupy  the  upper  part  of  the  cavity. 

Diving-bells  appear  to  have  been  first  introduced,  in  the 
beginning  of  the  sixteenth  century.  They  were  first  known 
as  objects  of  curiosity,  only,  but  have  been  since  applied 
to  tlie  recovery  of  valuable  articles  from  wrecks,  the 
blasting  and  mining  of  rocks,  at  the  bottom  of  the  sea, 
and  the  practice  of  submarine  architecture.  They  may  be 
made  of  almost  any  shape  ;  but  the  common  form  has  been 
that  of  a  bell,  or  hollow  cone,  m.ade  of  w^ooden  staves, 
and  strongly  bound  with  hoops,  having  seats  for  the  occu- 
pants, on  the  inside.  It  is  suspended  with  ropes,  from  a 
vessel  above,  and  is  ballasted  with  heavy  weights  at  bot- 
tom, which  serve  to  sink  it,  and  to  prevent  it  from  turn- 
ing over.  More  recently,  diving-bells  have  been  made  of 
cast-iron.  The  kind  of  bell  used  at  Howth,  near  Dub- 
hn,*  is  an  oblong  iron  chest,  six  feet  long,  four  broad, 
and  five  high,  thicker  at  bottom  than  at  top,  and  weighing 
four  tons.  It  has  a  seat  at  each  end,  and  is  capable  of 
holding  four  persons.  The  upper  part  is  pierced  with 
eight  or  ten  holes,  in  which  are  fixed  the  same  number  of 
strong  convex  glasses,  which  transmit  the  hght.  As  the 
air  in  the  bell  becomes  contaminated,  by  breathing,  it  is 
renewed,  by  letting  down  barrels,  or  small  bells,  of  fresh 
air,  which  is  transferred  to  the  large  bell  ;  or  else,  by 
keeping  up  a  constant  supply,  through  a  pipe,  by  nieans 
of  a  forcing  pump,  which  is  worked  by  men  at  the  sur- 
face. 

Persons  who  descend  in  diving-bells  often  experience 
a  \iam  in  the  ears,  and  a  sense  of  pressure,  occasioned  by 
the  condensation  of  the  air,  within  the  cavity  of  the  bell. 
These  symptoms  gradually  pass  off,  or  habit  renders  the 
body  indifferent  to  them,  so  that  workmen  remain  under 
water,  at  the  depth  of  twenty  feet  or  more,  for  seven  oj 
eight  hours  in  a  day,  without  detriment  to  the  health. 
♦Edinburgh  Philosophical  Journal,  vol.  v.  p.  8. 


SUBMARINE  NAVIGATION.  47 

Submarine  Js\ivigation. — A  machine  was  invented, 
during  the  American  Revolution,  by  Mr  Bushnell,  of 
Connecticut,  which  was  capable  of  containing  a  person  in 
safety,  under  water,  and  of  being  governed,  and  steered  in 
any  direction,  at  pleasure.  It  is  described*  as  being  a 
hollow  vessel,  of  a  spheroidal  form,  composed  of  curved 
pieces  of  oak,  fitted  together,  and  bound  with  iron  hoops, 
the  seams  being  caulked,  and  covered  with  tar,  to  render 
them  tight.  A  top,  or  head,  was  closely  fitted  to  the  ves- 
sel, and  served  the  purpose  of  a  door.  In  this  were  in- 
serted several  strong  pieces  of  glass,  to  admit  the  light. 
The  machine  contained  air  enough  to  render  it  buoyant, 
and  to  support  respiration.  A  quantity  of  lead  was  at- 
tached to  the  bottom,  for  ballast.  The  vessel  was  made 
to  sink,  by  admitting  water,  and  to  rise,  by  detaching  a 
part  of  the  leaden  ballast,  or  by  expelling  water  with  a 
forcing  pump.  It  was  propelled  horizontally,  by  means  of 
revolving  oars,  placed  obliquely,  like  the  sails  of  a  wind- 
mill, on  an  axis  which  entered  the  boat  through  a  tight 
collar,  or  water-joint,  and  was  turned  witli  a  crank  with- 
in. A  rudder  was  also  employed,  for  steering  the  vessel 
When  fresh  air  was  required,  the  vessel  rose  to  the  sur- 
face, and  took  in  air  through  apertures  at  the  top.  Tlie 
intention  of  this  machine  was,  to  convey  a  magazine  of 
powder  under  ships  of  war,  for  the  purpose  of  blowing 
them  up.  Several  experiments  were  made  with  it, 
which,  though  unsuccessful  in  their  object,  nevertheless 
proved  the  practicability  of  this  species  of  locomotion. 

The  late  Mr.  Fulton  made  various  experiments  on  sub- 
marine navigation,  in  a  boat  large  enough  to  contain  sev- 
eral persons,  furnished  with  masts  and  sails,  so  as  to  be 
capaole  of  proceeding  at  the  surface  of  the  water,  and, 
also,  of  plunging,  when  required,  below  the  surface. f 
While  under  water,  its  motions  were  governed  by  two 
machines,  one  of  which  caused  it  to  advance  horizontal- 
ly, while  the  other  regulated  its  ascent  and  descent,  its 
depth  below  the  surface  being  known,  by  the  pressure  on 
a  barometer.     A  supply  of  fresh  air  was  carried  down  in 

*  Silliman's  Journal,  vol.  ii.  p.  94. 

t  See  Colden's  Life  of  Fulton,  8vo.  New  York,  1810. 


48  ARTS   OF  LOCOMOTION. 

the  boat,  condensed  into  a  strong  copper  globe,  by  which 
the  air  of  the  boat  was  replaced,  when  it  became  unfit  for 
respiration.  Mr.  Fulton's  object  was  the  destruction  of 
ships  of  war,  by  bringing  underneath  them  an  explosive 
engine,  called  a  torpedo. 

AEROSTATION. 

Balloon. — A  Balloon  is  a  sphere,  or  bag,  formed  ol 
some  light  material,  such  as  silk,  and  rendered  impervi- 
ous to  the  air,  by  covering  it  with  elastic  varnish.  It  is 
filled  with  a  gaseous  fluid,  lighter  than  the  surrounding 
atmospheric  air,  and  has  a  car  suspended,  at  the  bottom. 
If  the  specific  gravity  of  the  whole  mass  is  less  than  that 
of  an  equal  bulk  of  the  atmospheric  air,  which  surrounds 
it,  the  balloon  will  ascend  into  the  atmosphere,  and  re- 
main suspended,  until,  by  the  escape  of  its  gas,  or  other 
means,  it  becomes  heavier  than  the  surrounding  air,  when 
it  will  again  descend.  Balloons  were  invented  in  France, 
by  the  Montgolfiers,  about  1782.  Those  which  were 
first  employed  by  them  were  filled  with  common  air, 
rarefied  by  heat ;  but  these  required,  that  a  fire  should  be 
constantly  kept  burning  beneath  them,  to  keep  them  afloat. 
Hydrogen  gas  was  afterwards  employed  ;  and  this  fluid, 
being  permanently  about  fourteen  times  less  dense  than 
common  air,  is,  undoubtedly,  the  best  material  for  aeros 
tation.  Carburetted  hydrogen,  though  heavier  than  hy- 
drogen, has  also  been  employed,  of  late,  on  account  of  its 
cheapness,  being  furnished,  in  large  quantities,  at  the  man- 
ufactories of  illuminating  gas. 

Balloons  are  made,  by  sewing  together  pieces  of  silk, 
the  shape  of  which  corresponds  to  that  of  the  part  includ- 
ed by  two  meridians  of  the  artificial  globe.  They  have 
also  been  made  of  linen,  and  of  paper.  They  are  var- 
nished with  a  solution  of  elastic  gum,  torrender  them  tight. 
A  net-work  is  thrown  over  the  top  of  the  balloon,  to 
which  is  attached,  by  strings,  a  car  of  wicker-work,  un- 
derneath the  balloon.  The  whole  is  kept  down,  by  a 
sufficient  quantity  of  ballast,  and  ascends  into  tiie  atmo- 
sphere, when  a  part  of  the  ballast  is  thrown  over.  It  is 
made  to  descend  again,  by  sufl^ering  a  part  of  the  gas  to 
escape  through  a  valve,  provided  for  the  purpose. 


PARACHUTE.  49 

The  regulation  of  the  ascent  and  descent  of  balloons 
is  the  extent  of  control,  which  has  been  hitherto  obtained 
over  them.  All  attempts  to  guide  or  propel  them,  by 
means  of  wings,  sails,  oars,  &c.,  have  hitherto  failed,  and 
the  machine  can  only  proceed  at  the  mercy  of  the  winds. 
The  small  degree  of  buoyancy,  which  balloons  possess, 
does  not  permit  them  to  carry  sufficient  weight  of  male- 
rial,  to  furnish  the  medium  of  an  adequate  propelling  force. 
By  taking  advantage,  however,  of  favorable  winds,  voy- 
ages have  been  made  in  them  to  the  distance  of  three 
hundred  miles  ;  and  persons  have  ascended  to  the  height 
of  twenty  thousand  feet,  and  upwards.  The  velocity  of 
balloons  varies  with  that  of  the  wind,  but  has,  in  some 
instances,  amounted  to  the  rate  of  seventy  miles  an  hour.* 

Parachute. — The  danger,  which  attends  falling  from 
great  heights,  is  in  consequence  of  the  continual  acceler- 
ation of  velocity,  which  faUing  bodies  experience.  When, 
however,  the  resistance  of  the  atmosphere  becomes  equal 
to  the  force  of  gravity,  the  motion  is  no  longer  acceler- 
ated, but  becomes  uniform.  A  parachute  is  an  appen- 
dage to  a  balloon,  formed  somewhat  like  an  umbrella,  and 
is  designed  to  break  the  force  of  a  fall,  by  means  of  the 
large  surface  which  it  opposes,  in  its  progress,  to  the  at- 
mosphere. It  is  made  of  silk  or  canvass,  and  is  placed 
underneath  the  balloon,  having  the  car  suspended  from  it 
by  cords.  When  the  balloon  is  at  any  height  in  the  air, 
the  parachute  may  be  detached  from  it,  and  will  imme- 
diately fall  with  the  car,  to  the  ground.  But  the  resistance 
of  so  large  a  surface  to  the  atmosphere,  causes  the  fall  to 
be  gradual  and  easy,  so  that  a  person  may  descend  with 
a  parachute,  in  safety,  from  the  greatest  heights.  The 
size  of  the  parachute,  employed  by  M.  Garnerin,  and 
with  which  he  descended  from  a  height  of  two  thousand 
feet,  at  Paris,  in  1797,  w^as  twenty-five  feet  in  diameter. 
The  parachute  was  folded  up,  at  the  beginning  oT  the  fall, 

*  M.  Gay-Lussac,  on  the  6th  of  September,  1804,  ascended  twen 
';y-three  thousand  and  one  hundred  feet  above  Paris.     M.  Garnerin, 
September  21st,  1827,  passed,  in  seven  hours  and  a  half,  from  Paris 
to  Mount  Tonnere,  a  distance  of  three  hundred  miles.     This  voyage 
was  performed  in  the  night,  and  daring  a  storm. 

II.  5  XII 


50  ELEMENTS  OF  MACHINERY. 

but  soon  expanded  itself,  by  the  resistance  of  the  atmo- 
sphere. The  only  inconvenience,  which  was  experienced> 
arose  from  a  violent  oscillating  motion. 

Works  of  Reference. — Brewster's  Edition  of  Ferguson 
Lectures  on  Mechanics,  &c.  2  vols.  8vo.  1823  ; — ANSTiCE,on  Whee 
Carriages  ; — EdgewortHjOD  Roads  and  Carriages,  Svo  ; — Depar- 
ciEUx  sur  letirage  des  chevaux,  in  the  Mem.  de  VAcad.  Paris,  1760  ; 
— Yovng's  Lectures  on  Natural  Philosophy  ; — McAdam,  on  roads, 
Svo.  1823  ; — Blvnt  and  Stevenson's  Civil  Engineer,  fol.  1834, 
&c.  ; — Parnell,  Treatise  on  Roads,  8vo.  1833  ; — Tredgold, 
on  Rail  Roads,  Svo.  1825  ; — Wood,  on  Rail  Roads,  Svo.  1825  ; — 
Strickland's  Reports  on  Canals,  Rail  Roads,  &c.,  oblong  fol.  Phil 
ad.,  1820  ; — Article  Canal,  in  Rees'  Cyclopedia,  written  by  Mr.  J. 
Farey  ;  Articles  Navigation  Inland,  Railway,  Bridges,  Aeronautics, 
&c.,  in  the  Edinburgh  Encyclopedia  ; — Chapman,  on  Canal  Naviga- 
tion, 4to.  1797  ; — Fulton,  on  Canal  Navigation,  4to.  1796  ; — Smea- 
ton's  Reports,  3  vols.  Svo.  1812  ; — Prony,  Architecture  Hydrau- 
lique,  2  torn.  4to.  1790  ; — Belidor,  Architecture  Hydraulique,  4 
torn.  4to.  1750  ; — De  Cessart,  Travaux  HydrauliqueSy  2  torn.  4to. 
1808  ; — Reports  to  the  House  of  Commons  on  Roads,  Steam  Boats, 
&c.,  1822,  &c.  ; — Article  Seamanship,  in  the  Encyclopedia  Brittani- 
ca,  by  Prof.  Robinson  ; — Dupin,  Voyage  dans  la  Grand  Bretagne, 
6  vols.  Svo.  with  plates,  fol.  1825. 


CHAPTER  XV. 

ELEMENTS   OF    MACHINERY. 

Machines,  Motion.  Rotary,  or  Circular,  Motion,  Band  Wheels, 
Rag  Wheels,  Toothed  Wheels,  Spiral  Gear,  Bevel  Gear,  Crown- 
wheels, Universal  Joint,  Perpetual  Screw,  Brush  Wheels,  Ratchet 
Wheel,  Distant  Rotary  Motion,  Change  of  Velocity,  Fusee.  Al- 
ternate, or  Reciprocating,  Motion,  Cams,  Crank,  Parallel  Motion, 
Sun  and  Planet  Wheel,  Inclined  Wheel,  Epicydoidal  Wheel,  Rack 
and  Segment,  Rack  and  Pinion,  Belt  and  Segment,  Scapements. 
Continued  Rectilinear  Motion,  Band,  Rack,  Universal  Lever, 
Screw,  Change  of  Direction,  Toggle  Joint.  Of  Engaging  and  Dis- 
engaging Machinery.  Of  Equalizing  Motion,  Governor,  Fly 
Wheel.     Friction.    Remarks. 

JUachines. — By  a  machine,  may  be  understood  a  com- 
bination of  mechanical  powers,  adapted  to  vary  the  di- 
rection, apphcation,  and  intensity,  of  a  moving  force,  s<? 


MOTION. ROTARY,   OR  CIRCULAR,  MOTION.        *! 

as  to  produce  a  given  result.  The  advantage  which  ma- 
chines possess,  over  common  manual  labor,  is  generally 
that  of  increasing,  or  improving,  the  product  of  an  oper- 
ation. This  end  they  accomphsh,  by  enabling  us  to  ap- 
ply a  common  force,  more  advantageously,  or  to  employ 
the  most  powerful  force,  derived  from  natural  agents,  with 
precision  and  efficacy.  By  the  aid  of  machinery,  any 
number  of  instruments,  or  operative  parts,  may  be  made 
to  move  in  concert,  in  every  possible  direction,  with  any 
degree  of  velocity,  and  to  reciprocate  with  each  other 
in  perfect  harmony,  so  that  complex  operations  are  per- 
formed by  them,  with  a  precision  which  often  exceeds 
the  skill  of  the  most  expert  artist. 

Motion. — The  motion  which  takes  place  in  machines 
is,  for  the  most  part,  either  rotary  or  reciprocating.  A 
rotary  motion  is  that,  in  which  the  moving  parts  revolve 
round  an  axis,  as  in  a  wheel,  a  crank,  or  a  fly.  A  recip- 
rocating, or  alternate,  motion  is  that,  in  which  a  body  re- 
traces its  own  path,  or  moves  alternately  backward  and 
forward,  in  the  same  track,  which  may  be  curved,  as  in 
the  beam  of  a  steam-engine,  or  rectilinear,  as  in  the  pis- 
ton. Most  compound  machines  possess  both  these  kinds 
of  motion,  or  varieties  derived  from  them  ;  and  the  dif- 
ferent ways  of  producing  and  communicating  them,  in  the 
requisite  times  and  places,  constitute  a  principal  subject 
of  attention  with  machinists. 

ROTARY,  OR  CIRCULAR,  MOTION. 

When  it  is  intended  that  one  wheel,  or  axle,  shall  pro- 
pel another,  various  contrivances  are  adopted,  to  connect 
the  propelling  part  w^ith  that  which  is  to  be  moved.  The 
mode  of  connexion  is  varied,  according  to  the  distance, 
the  relative  velocity  required,  and  the  direction  in  which 
motion  is  to  be  communicated. 

Band  Wheels. — If  two  wheels  be  connected  by  a  belt, 
or  band,  passing  round  their  circumferences,  they  will 
move  simultaneously,  provided  the  friction  of  the  band~ 
is  sufficient  to  prevent  it  from  slipping.  When  a  round 
cord  is  used,  any  degree  of  friction  may  be  produced,  by 
receiving  the  cord  in  a  sharp  groove,  at  the  edge  of  the 


52 


ELEMENTS    OF  MACHINERY. 


wheel.  But  the  stiffness  of  cords  forms,  in  nnaiiy  cases, 
an  objection  to  their  use.  When  a  strap,  or  flat  band,  is 
used,  its  friction  may  be  increased,  by  increasing  its  width. 
The  surface  at  the  circumference  of  a  wheel,  or  drum, 
which  carries  a  flat  band,  should  not  be  exactly  cylindri- 
cal, but  a  little  convex  ;  in  which  case,  if  the  band  in- 
cHnes  to  slip  off,  at  either  side,  it  returns  again,  by  the 
tightening  of  its  inner  edge,  as  may  be  seen  in  a  turner'? 
lathe.  When  wheels  are  connected,  in  the  shortest  man- 
ner, by  a  band,  as  in  Fig.  105,  they  move  in  the  same 


Fig.  105. 


Fig.  106. 


direction.  If  the  band  be  crossed,  as  in  Fig.  106,  they 
will  move  in  opposite  directions.  Wheels,  whose  axes 
are  situated  in  different  planes,  may  turn  each  other,  if 
the  band  be  sufficiently  long.  If  no  slipping  were  to  take 
place  in  the  band,  wheels  of  equal  size  w^ould  move  with 
equal  velocity,  and  those  of  different  sizes,  wath  velocities 
inversely  proportionate  to  their  respective  circumferen- 
ces. But,  since  the  band  is  liable  to  yield  or  slide,  some- 
what, during  the  revolution,  the  velocity  of  the  driven 
wheel  is,  commonly,  a  little  less,  in  proportion,  than  that 
of  the  wheel  which  drives  it. 

Rag  Wheels. — Where  it  is  necessary  that  the  veloci- 
ties should  be  exactly  proportionate,  also,  where  great 
resistance  is  to  be  overcome,  chains  of  various  kinds  are 
substituted,  by  passing  them  round  wheels,  in  the  place 
of  belts  and  ropes.  These  chains  lay  hold  upon  pins,  or 
enter  into  notches,  on  the  circumference  of  the  wheels,  so 
as  to  cause  them  to  turn  simultaneously.  Such  wheels 
are  denominated  rag-wheels^  and  have  a  uniform  relative 


TOOTHED  WHEELS.  53 

velocity.  [Fig.  107.]    They  are  used  in  locomotive  steam* 
engines,  chain  water-wheels,  &c. 

Fig.  107-. 


Toothed  Wheels. — Toothed  wheels  afford  a  more  re- 
gular and  effectual  mode  of  communicating  rotary  motion, 
than  any  other  kind  of  connecting  mechanism.  They 
move,  of  necessity,  in  opposite  directions,  and  their  rela- 
tive velocity  is  inversely  proportionate  to  their  number  of 
teeth.  Thus,  if  a  wheel  having  forty  teeth  drives  another 
of  ten  teeth,  the  second  will  make  four  revolutions,  while 
the  first  makes  one.  The  connexion  of  one  toothed  wheel 
with  another  is  called  gear^  or  gearing  ;  and,  when  both 
wheels,  with  their  teeth,  are  in  the  direction  of  the  same 
plane,  it  is  called  spur-gearing.  It  is  desirable,  in  tooth- 
ed wheels,  as  far  as  possible,  to  diminish  friction,  and  to 
produce  uniformity  of  force  and  motion.  A  uniform  mo- 
tion may  be  produced,  if  the  form  cl  the  acting  face  of 
the  teeth  be  a  curve  of  the  epicycloidal  Aind  ;  the  outline 
of  the  teeth  of  one  wheel  being  the  curve  w'/iich  would 
be  described,  by  the  revolution  of  a  curve  upor.  a  g>en 
circle,  while  the  outline  of  the  teeth  of  the  other  wheel  is 
described,  by  the  same  curve  rolling  within  the  circle.  It 
may  also  be  produced,  if  the  teeth  of  one  wheel  be 
straight,  circular,  or  of  any  regular  figure,  whatever  ;  pro- 
vided the  teeth  of  the  other  wheel  be  of  a  figure,  com- 
pounded of  that  figure  and  of  an  epicycloid.* 

Of  two  wheels,  which  are  unequal  in  size,  the  larger  is 
called  the  wheel.,  and  the  smaller,  the  pinion.  The  act- 
ing portions  of  the  wheel  are  called  teeth ;  and,  of  the 

*  For  investigations  relating  to  the  teeth  of  wheels,  see  Camus,  on 
the  Teeth  of  Wheels,  translated,  London,  8vo.  1806  ; — Buchanan,  on 
Mill  Work,  chap.  i.  &c.  ; — Brewster's  Ferguson's  Lectures,  vol.  ii. 
p.  119  ; — Gregory's  Mechanics,  vol.  ii.  p.  451  ; — also,  a  Treatise,  by 
Mr.  Blake,  in  Silliman's  Journal,  vol.  vii.  p.  86. 
*5 


54 


ELEMENTS   OF  MACHKNERY. 


pinion,  more  commonly,  leaves.  The  name  of  lanterns 
is  given  to  pinions  with  two  heads,  connected  by  cyhn- 
drical  teeth,  or  trundles.     In  Fig.  lOS,  the  line,  joining 


Fig.  108 


tho  centres,  B  and  F,  of  the  wheel  and  pinion,  is  called 
the  line  of  centres,  and,  when  this  line  is  divided  into  two 
parts,  FA  and  BA,  which  are  to  each  other,  as  the 
number  of  leaves  in  the  pinion  is  to  the  number  of  teeth 
in  the  wheel,  BA  is  called  the  primitive  radius*  of  the 
wheel,  and  FA,  the  primitive  radius  of  the  pinion  ;  while 
the  lines,  or  distances,  Ff  and  Bb,  are  called  the  true  radii. 
The  circles,  X  AX  and  RAFt,  are  called  the  primitive  cir- 
cumferences, and,  by  workmen,  the  pitch  lines. 

Friction,  to  a  certain  extent,  cannot  be  avoided,  in 
teeth  of  the  common  kind,  whose  acting  faces  are  at  right 
angles  with  the  plane  of  the  wheels,  to  which  they  belong. 
It  may,  however,  be  much  diminished,  by  making  the 
teeth  as  small  and  as  numerous,  as  is  consistent  with  their 
strength  ;  for  the  quantity  of  friction  necessarily  increases, 
with  the  distance  of  the  point  of  contact  from  the  line  of 
centres. 

♦  Called  the  proportional  radius,  by  Buchanan 


SPIRAL   GEAR.  65 

tSpiral  Gear. — In  common  cases,  the  teeth  of  wheels 
are  cut  across  the  circumference,  in  a  direction  parallel 
to  the  axis.  In  the  spiral  gear,  now  much  used  in  cotton 
mills,  in  this  country,  the  teeth  are  cut  obliquely,  so  that, 
if  continued,  they  would  pass  round  the  axis,  like  the 
threads  of  a  screw.  In  consequence  of  this  disposition, 
the  teeth  come  in  contact  only  in  the  line  of  centres,  and 
thus  operate  without  friction.     [Fig.  109  J      The  action 


of  these  wheels,  it  is  true,  is  compounded  of  two  forces, 
one  of.  which  acts  in  the  direction  of  the  plane  of  the 
wheel,  and  the  other  in  the  direction  of  its  axis.  The 
latter  force  occasions  a  degree  of  friction,  w'hich,  being 
expended  at  the  end  of  the  axle,  may  be  regarded  as  in- 
considerable. The  remaining  force  goes  to  produce  ro- 
tary motion. 

The  spiral  gearing  has  been  apphed  to  clock-work,  and 
has  the  peculiarity,  that  it  admits  of  a  smaller  pinion  than 
any  other  gearing.  Thus,  if  a  very  small  cylinder  have 
a  spiral  groove  so  cut  in  it,  as  to  extend  once  round  its 
circumference,  it  will  perform  one  revolution  for  every 
tooth  of  the  wheel  which  drives  it.  The  groove  may  be 
cut  indefinitely  near  to  the  centre  of  the  pinion,  or  cylin- 
der, without  weakening  it  so  much  as  would  happen  in 
other  forms  of  the  pinion.* 

*  The  spiral  gear  has  been  used  at  Waltham,  Mass.,  and  elsewhere, 
for  about  fifteen  years,  and  is  commonly  considered,  here,  as  the  inven- 
tion of  Mr.  White.  Something  analogous  to  it,  under  the  name  of 
Inclined  Plane  Wheels,  was  published  in  London,  by  Mr.  T.  Shel- 
'drake,  in  1811. 


56 


ELEMENTS   OF  MACHINERY, 


Bevel  Gear. — When  wheels  are  not  situated  in  the 
same  plane,  but  form  an  angle  with  each  other,  the  spur 
gearing,  already  described,  is  changed  for  teeth  of  a  dif 
ferent  description.  In  this  case,  the  bevel  gearing  is 
commonly  employed,  consisting  of  wheels,  which  are 
frusta  of  cones,  having  their  teeth  cut  obliquely,  and  con- 
verging toward  the  point,  where  the  apex  of  the  cone 
would  be  situated.  According  as  the  relative  magnitude 
of  the  wheels  varies,  the  angle  of  the  bevel  must  be  dif- 
ferent, so  that  the  velocities  of  the  wheels  may  be  in  the 
same  proportion,  at  both  ends  of  their  oblique  sides,  or 
faces.  For  this  purpose,  the  faces  of  all  the  teeth  must 
be  directed  to  the  point,  where  the  axes  of  the  two  wheels 
would  meet.     The  bevel  gearing  is  shown  in  Fig.  110, 


and  Fig.  116. 


Fig.  110. 


Crown  Wheels. — Circular  motion  is  also  communicat- 
ed, at  right  angles,  by  means  of  teeth  or  cogs,  situated 
parallel  to  the  axis  of  the  wheel.  Wheels,  thus  formed, 
are  denominated  crown,  or  contrate.,  w^heels.  They  act 
either  upon  a  common  pinion,  or  upon  a  lantern.  The 
crown-wheel  is  represented  in  Fig.  111.  It  is  less  m  use 
than  the  bevel-gear,  before  described,  having  more  friction 


UNIVERSAL  JOINT. PERPETUAL  SCREW.  57 

Universal  Joint. — The  contrivance  called  Hooke's 
universal  joint,  is  sometimes  used,  instead  of  wheels,  to 
communicate  circular  motion  in  an  oblique  direction.  It 
consists  of  two  shafts,  or  axes,  each  terminating  in  a 
semicircle,  and  connected  together  by  means  of  a  cross, 
upon  which  each  semicircle  is  hinged.    [Fig.  112.]    It  is 

Fk.  112. 


obvious,  that  when  one  shaft  is  turned,  the  other  must  re- 
volve likewise  ;  and  this  will  be  the  case,  whenever  the 
angle,  by  which  one  shaft  deviates  from  the  direction  of 
the  other,  does  not  exceed  forty  degrees.  By  means  of 
a  double  universal  joint,  circular  motion  may  be  com- 
municated, at  an  angle  of  from  fifty  to  ninety  degrees. 

Perpetual  Screw. — The  perpetual,  or  endless,  screw, 
sometimes  called  loorm^  by  mechanics,  is  made  use  of  to 
convey  circular  motion  from  an  axle  to  a  toothed  wheel, 
situated  in  the  direction  of  the  same  plane  with  the  axle. 
The  relative  velocity  of  a  wheel  driven  by  a  screw  is  very 
slow  ;  for,  if  the  screw  have  only  a  single  thread,  the 
wheel  will  advance  the  breadth  of  one  tooth,  only,  for  eacb 

Fig.  113. 


kS 

aa 


53  ELEMENTS   OF  MACHINERY. 

revolution  of  the  screw.  This  mechanism  is  of  great  use 
in  producing  an  equable  slow  motion,  in  machinery,  and 
also,  in  increasing  mechanical  power.  [Fig.  113.]  The 
motion  may  be  reversed,  or  conveyed  from  the  wheel  to 
the  screw,  if  the  obliquity  of  the  threads  be  sufficiently 
increased.  A  spiral  wheel  and  a  toothed  wheel  may  be 
made  to  turn,  with  equal  velocity,  or  any  desired  propor- 
tion of  velocity,  by  the  construction  represented  in  Fig. 
/  ^4.     A,  is  a  wheel,  seen  edgeways,  its  axis  being  BC. 


B<:  /^z^c 


Its  circumference  is  furnished  with  spiral  ridges,  which, 
as  the  wheel  turns,  cause  the  pinion,  D,  to  revolve  in  the 
plane  of  the  axis,  BC. 

Brush  Wheels. — In  light  machinery,  wheels  sometimes 
turn  each  other  by  means  of  bristles,  or  brushes,  fixed  to 
their  circumference.  They  may,  also,  communicate  cir- 
cular motion,  by  friction  only.  In  this  case,  the  surface 
brought  in  contact  is  formed  of  the  end-grain  of  wood,  or 
it  is  covered  with  leather,  or  some  other  elastic  substance, 
and  the  two  wheels  are  pressed  together,  to  increase  the 
friction. 

Ratchet  Wheel. — The  ratchet,  or  detent,  wheel  is  in- 
tended to  prevent  motion  in  one  direction,  while  it  per- 
mits it  in  another.  For  this  purpose,  the  teeth  are  cut 
with  their  faces  inclining  in  one  direction,  and  a  small 
lever,  or  catch,  is  so  placed,  as  to  enter  the  indentations, 
and  stop  the  wheel,  if  it  turns  backward,  but  slides  ovei 
the  teeth,  without  obstructing  them,  if  it  moves  forward. 
[Fig.  115.]     Ratchet-wheels  are  generally  employed  to 


DISTANT   ROTARY  MOTION.  69 

pres^ent  a  weight,  raised  by  a  machine,  from  descending, 
and  to  obviate  other  retrograde  movements. 

Fig.  115. 


Distant  Rotary  Motion. — When  it  is  required  to  trans- 
mit circular  motion  to  a  distance,  for  example,  from  one 
extremity,  or  story,  of  a  building,  to  another,  various  meth- 
ods are  employed.  The  most  common  is,  by  band-wheels, 
or  drums,  connected  by  leather  belts  of  the  requisite  length. 
This  mode  is  considered  most  economical.  -When  a 
precise  velocity  is  required,  a  rolling  shaft,  geared  at  both 
ends,  as  in  Fig.  116,  is  to  be  preferred.     A  double  crank. 

Tier.   116. 


having  its  two  parts  at  right  angles  with  each  other,  and 
connected  with  a  similar  crank,  by  stiff  rods,  or  bars,  an- 
swers the  same  purpose.    [Fig.  1 17.]    If  triple  cranks  are 


Fig.  117. 


used,  cords  will  serve,  instead  of  bars,  for  connection,  be- 
cause, in  this  case,  some  part  of  the  first  crank  will  always 
be  in  a  situation  to  draw  the  second,  and  a  rigid  medium 
will  not  be  necessary. 


60  ELEMENTS   OF  MACHINERY. 

Change  of  Velocity. — It  is  sometimes  necessary,  thai 
a  machine  should  be  propelled  with  a  velocity  which  is 
not  equable,  but  which  continually  changes,  in  a  given 
ratio.  This  happens  in  cotton-mills,  where  it  is  neces- 
sary that  the  speed  of  certain  parts  of  the  machinery 
should  continually  decrease,  from  the  beginning  to  the  end 
of  an  operation.  To  effect  this  object,  two  cones,  or 
conical  drums,  are  used,  having  their  larger  diameters  in 
opposite  directions.  They  are  connected  by  a  belt,  which 
is  so  governed,  by  proper  mechanism,  that  it  is  gradually 
moved  from  one  extremity  of  the  cones  to  the  other,  thus 
acting  upon  circles  of  different  diameter,  causing  a  con- 
tinual change  of  velocity  in  the  driven  cone,  with  relation 
to  that  which  drives  it.      [Fig.  118.] 


A  change  of  speed  is  also  effected,  by  a  decreasing  series 
of  toothed  wheels,  placed,  in  the  order  of  their  size,  upon 
a  common  axis,  and  fixed.  A  corresponding  series,  in  an 
inverted  order,  are  placed  upon  another  axis,  and  not 
fixed,  but  capable  of  revolving  about  the  axis,  like  loose 
pullies.  The  axis  of  this  second  series  is  made  hollow, 
and  contains  a  movable  rod,  which  has  a  tooth,  project- 
ing through  a  longitudinal  slit  in  one  side  of  the  axis.  This 
tooth  serves  to  lock  any  one  of  the  wheels,  by  entering  a 
notch,  cut  for  its  reception.  Only  one  wheel,  however, 
can  be  locked  at  a  time,  the  others  remaining  loose,  so 
that  the  axis  will  revolve  with  a  velocity,  which  is  due  to 
the  relative  size  of  the  particular  wheel  which  is  locked, 
and  of  the  wheel  which  drives  it.  By  successively  lock- 
ing the  different  wheels,  an  increase,  or  decrease,  of  speed 
is  obtained.*     [Fig.  119.] 

*  A  mechanism  of  this  kind  is  used  in  the  cotton  factory  at  New- 
ton, Massachusetts,  and  there  is  one,  nearly  similar,  in  Bramah's  plan- 
ing machine. 


CHANGE   OF  VELOCITY 

Fig.  119. 


61 


Another  mode  of  changing  speed  is  produced,  by  a 
large,  and  small,  wheel,  placed  at  right  angles  with  each 
other,  and  acting  by  friction  only.  The  edge  of  the 
smaller  wheel  is  kept  in  close  contact  with  the  disc,  or 
flat  surface,  of  the  larger  wheel,  so  that  the  smaller  wheel 
will  revolve  faster,  or  slower,  according  to  the  distance, 
at  which  it  is  kept  from  the  centre  of  tLe  larger  wheel. 
The  distance  may  be  varied  at  pleasure       [Fig.  120.] 

Fig.  120. 


It  is  sometimes  requisite  that  a  wheel,  or  axis,  should 
move  with  different  velocity,  in  different  parts  of  a  single 
revolution,  as  in  orreries,  &c.  This  may  be  effected,  by 
an  eccentric  crown-wheel,  acting  on  a  long  pinion   as  in 


l(. 


¥11, 


62  ELEMENTS   OF  MACHINERY. 

Fig.  121.  It  may  also  be  accomplished  in  a  different 
way,  by  a  cone,  furnished  with  spiral  line  of  teeth,  acting 
on  another  cone,  the  position  of  which  is  reversed. 

Fusee. — In  the  preceding  arrangements  for  changing 
velocity,  there  is  a  corresponding  change  of  force,  which 
is  in  an  inverse  ratio  to  the  change  of  velocity.  They 
may,  therefore,  be  employed  for  varying  force,  as  well 
as  speed.  The  fusee  of  a  common  watch  is  a  contriv- 
ance, adapted  to  this  purpose.  "When  a  watch  is  recent- 
ly wound  up,  the  spring,  which  propels  it,  is  in  the  state  of 
greatest  tension.  As  this  spring  relaxes,  or  uncoils  itself, 
its  power  decreases,  and,  in  order  to  correct  this  inequal- 
ity, the  chain,  through  which  it  acts,  is  wound  upon  a  spi- 
ral fusee.  The  fusee,  B,  is  an  axis,  surrounded  by  a  spiral 
groove,  the  distance  of  the  groove  from  the  axis  being 
made  to  increase  gradually,  from  the  top  to  the  bottom,  so 
that,  in  proportion  as  the  force  of  the  spring  is  diminished, 
it  may  act  on  a  longer  lever.  The  general  outline  of  the 
fusee  must  be  nearly  such,  that  its  thickness,  at  any  part, 
may  diminish,  in  the  same  proportion  as  it  becomes  more 
distant  from  the  point,  at  which  the  force  would  cease 
altogether,  the  general  curve  being  that  of  a  hyperbole  ; 
\)ut  the  workmen  have,  in  general,  no  other  rule,  than  that 
of  habitual  estimation.      [Fig.  122.] 

Fig.  122. 


ALTERNATE,   OR  RECIPROCATING,  MOTION. 

This  name  is  applied  to  movements  which  take  place 
continually,  backwards  and  forwards,  in  the  same  path. 
An  alternate  motion  may  take  place  about  a  centre,  in 
which  case,  the  moving  parts  will  describe  arcs  of  circles, 
as  in  a  tilt-hammer,  or  the  beam  of  a  steam-engine  ;  or  it 
may  be  confined  by  guides,  so  as  to  pursue  a  rectilinear 
path,  as  in  the  saw  of  a  saw-mill.     In  most  complex  ma- 


CAMS. 


63 


chines,  both  rotary  and  reciprocating  motions  occur,  and 
these  motions  are  convert"^d  into  each  other,  by  any  of  the 
following  contrivances. 

Cams. — If  the  axis  of  a  wheel  be  situated  in  any  other 
point  than  its  centre,  the  wheel,  thus  rendered  eccentric, 
may  produce,  by  its  revolution,  an  alternate  motion  in  any 
part  exposed  to  its  action.  Circles,  hearts,  ellipses,  parts 
of  circles,  and  projecting  parts  of  various  forms,  are  made 
to  produce  alternate  motion,  by  continually  altering  the 
distance  of  some  movable  part  of  the  machine,  from  the 
axis  about  which  they  revolve.  Such  projecting  parts 
are  called  cams.*  In  the  various  forms  which  are  shown 
in  the  figures,  the  part,  removed  by  the  cam,  is  supposed 
to  return,  by  its  own  gravity,  or  by  some  other  power,  so 
as  to  keep  up  the  alternate  motion.  In  the  circular  ec- 
centric cam,  or  wheel,  [Fig.  123,]  the  sliding,  or  recipro- 
cating, part,  x\B,  will  ascend  and  descend,  with  an  easy 
motion,  being  never  at  rest,  unless  at  the  instant  of  chang- 
ing its  direction.  Eccentric  wheels,  if  surrounded  by  a 
hoop,  as  at  H,  in  PI.  IX.  perform  the  same  office  as 
cranks.  In  the  semicircular  cam,  [Fig.  124,]  the  recipro- 
cating part  will  remain  at  rest,  on  the  periphery  of  the  cam, 
during  half  the  revolution,  but,  in  the  remaining  half,  it 
w'ill  approach  the  axis,  and  return.  In  the  quadrant  cam, 
[Fig.  125,]  the  reciprocating  part  will  remain  at  rest,  on 
the  periphery,  during  the  first  quarter  of  the  revolution  ; 


Fig.  123. 
A 


1 


Fig.  124. 
A 


o 


Fig.  125. 
A 


Fig.  126 
A 


o 


Fig.  127. 
A 


^B    r-^B   ^B^B 


S 


^       ^  / 


:^  c 


*  This  word  is  spelt  cam,  camm,  and  camb,  by  different  writers. 
In  French  came. — Borgni^. 


64 


ELEMENTS   01   MACHINERY, 


during  the  second,  it  will  descend  to  the  axis  ;  during  the 
Third,  it  will  be  at  rest  upon  the  axis  ;  and  during  the  fourth, 
it  will  return  to  its  original  situation.  The  narrow  cam, 
[Fig.  126,]  causes  the  reciprocating  part  to  rise  and  fall, 
in  one  half  the  revolution,  and  to  remain  at  rest,  on  the  axis, 
during  the  other  half.  In  these  figures,  the  angles. of  the 
cams  are  made  sharp,  for  the  sake  of  demonstration  ;  but, 
in  practice,  they  are  generally  rounded,  to  produce  more 
gradual  changes  of  motion.  The  elhptical  cam,  [Fig. 
127,]  causes  two  alternate  movements  for  each  revolution  ; 
and  the  triple  cam,  in  Fig.  12S,  apphed  to  a  tilt,  or  trip, 

Fig.  128. 


hammer,  causes  three  strokes  for  one  revolution.  In  thi: 
case,  the  cams  are  called  icipers,  and  it  is  common  to 
accelerate  the  reciprocal  motion,  by  adding  to  the  action 
of  gravitation,  the  elastic  force  of  a  spring,  or  by  the  re- 
coil of  the  handle  from  a  fixed  obstacle.  A  cam,  in  the 
form  of  a  heart,  called  a  heart-wheel^  is  much  used  in 
cotton-mills,  to  cause  a  regular  ascent  and  descent  of  the 
rail  on  which  the  spindles  are  situated.* 

When  an  easy  motion  is  desired,  as  in  most  large  ma- 
chinery, the  acting  outline  of  the  cam  should  be  curved  . 
but,  to  produce  a  sudden  stroke,  it  should  be  straight 
The  number  of  cams  may  be  indefinitely  multiplied,  if  a 
rapid,  or  vibrating  movement,  is  required.  This  is,  in 
effect,  done,  when  the  teeth  of  a  wheel  act  upon  a  spring, 
or  weight,  as  in  a  watchman's  rattle,  or  in  the  feeder  of 
a  grist-mill. 

*  For  an  investigation  of  the  curves  proper  for  different  cams  and 
wipers,  see  Brewster's  edition  of  Ferguson's  Mechanics,  vol.  ii.  p.  126, 
&c.  For  producing  an  easy  and  uniform  motion,  spiral,  epicycloidal, 
and  other  curves,  are  requisite  ;  but,  for  abrupt,  forcible,  motions,  such 
as  occur  in  tilt-hammers,  curves  of  equal  action  are  to  be  avoided. 


CRANK. PARALLEL  MOTION. 


65 


Crank. — The  common  crank  affords  one  of  the  simp- 
lest and  most  useful  methods,  for  changing  circular  into 
alternate  motion,  and  vice  versa.  The  single  crank,  [Fig. 
129,]  can  only  be  used  upon  the  end  of  an  axis.  The 
bell-crank,  [Fig.  130,]  may  be  used  in  any  part  of  an  axis. 
The   double  crank,  [Fig.  131,]  produces  two  alternate 


Fig.  129. 


Fig.  130. 


Fig.  131. 


M        uT     rt 


ir 


motions,  reciprocating  with  each  other.  The  alterna- 
ting parts,  in  all  these  cases,  are  attached  to  the  crank 
by  connecting  rods,  or  by  some  of  the  kinds  of  mechan- 
ism, hereafter  described.  The  motion,  produced  by 
cranks,  is  easy  and  gradual,  being  most  rapid,  in  the  mid- 
dle of  the  stroke,  and  gradually  retarded,  toward  the 
extremes  ;  so  that  shocks  and  jolts,  in  the  moving  ma- 
chinery, are  diminished,  or  wholly  prevented,  by  their  use. 
Parallel  Motion. — The  name  of  parallel  motions  is  giv- 
en to  those  arrangements,  which  convert  circular  motion, 
whether  continued  or  alternate,  into  alternate  rectilinear 
motion,  and  vice  versa.  Thus,  the  beam  of  a  steam-en- 
gine moves  in  circular  arcs,  while  the  piston  moves  in 
right  lines.  They  cannot,  therefore,  be  rigidly  connect- 
ed together,  without  doing  violence  to  the  machine  ;  and 
it  becomes  necessary  to  convert  one  movement  into  the 
other,  by  the  intervention  of  proper  mechanism.  A  mov- 
able parallelogram  is  principally  used,  for  this  purpose, 
and  will  be  described  under  the  head  of  Steam  Engine. 
A  similar  contrivance,  of  a  more  simple  form,  is  shown  in 
Fig.  132.  CD,  is  a  rod,  moving  back  and  forwards,  in  a 
right  line.     Every  point  of  junction  is  a  hinge,  or  joint. 


66 


ELEMENTS   OF  MACHINERY. 


GE,  is  a  rod,  movable  about  E,  as  a  centre  ;  and  FH,  a 
rod  of  the  same  length,  movable  about  F,  as  a  centre  ; 
these  centres  being  equally  distant  from  the  path  of  CD. 
GH,  is  a  bar,  connecting  these  two  rods,  and  havmg  the 
rod,  CD,  attached,  by  a  joint,  to  its  centre.  When  the 
whole  is  set  in  motion,  the  joint,  G,  will  describe  the  cir- 
cular arc,  IK,  and  the  joint,  H,  will  describe  the  circulai 
arc,  GH,  while  the  joint,  C,  will  pursue  an  intermediate, 
or  rectihnear,  course. 

Various  other  methods  are  practised,  to  insure  a  rectili- 
near motion,  though  most  of  them  are  attended  with  great 

Fig.  133. 


SUN  AND  PLANET  WHEEL. 


67 


er  friction  than  that  last  described.  Thus,  the  alternating 
part  is  often  confined  to  a'rectilinear  path,  by  shding  in 
grooves,  guides,  or  holes,  or  between  friction  wheels  ;  a 
connecting  rod  uniting  the  straight  and  circular  motions, 
as  in  the  last  instance.  In  Cartwright's  steam-engine, 
the  straight  movement  of  the  piston  is  secured,  by  con- 
necting it  with  two  cranks,  acting  in  opposition  to  each 
other,  and  having  their  axles  geared  together  by  wheels, 
as  represented  in  Fig.  133,  on  page  6G, 

The  connecting  rod  may  be  dispensed  with,  if  a  trans- 
verse groove,  or  slit,  be  cut  in  the  alternating  part,  of  a 
length  equal  to  the  diameter  of  the  crank's  revolution ; 
as  in  Fig.  1 34.     The  end  of  the  crank,  seen  at  [o,]  in  its 

Fig.  134. 


revolution,  traverses  the  whole  length  of  this  groove,  which 
is  cut  in  the  crossbar,  AB,  while  the  main  bar,  CD,  has 
an  alternate  motion  in  the  straight  path  to  which  it  is  con- 
fined. As  the  space  of  ascent,  or  descent,  of  the  bar, 
CD,  is  always  equal  to  the  versed  sine  of  the  arc  described 
by  the  crank,  the  motion  of  the  bar  will  be  accelerated, 
towards  the  middle  of  its  oscillations,  and  retarded,  to- 
wards the  extremes.  A  more  equal  motion  can  be  pro- 
duced, if  desired,  by  substituting  for  the  straight  groove, 
a  curvilinear  groove,  somewhat  like  the  figure  co  ;  but 
this  method  is  attended  with  much  friction,  and  little  use. 
Sun  and  Planet  Wheel. — The  mechanism  which 
bears  this  name,  was  invented  by  Mr.  Watt,  to  convert 


68  ELEMENTS    OF  MACHINERY. 

reciprocating  into  circular  motion,  in  the  steam-engine  , 
the  use  of  the  crank,  for  this  purpose,  being,  at  one  time, 
secured  by  patent  to  another  individual.     In  Fig.  135,  a 


view  is  given  of  the  sun  and  planet  wheel.  A,  is  the  end 
of  a  beam,  having  a  reciprocating  motion.  B,  is  the  fly- 
wheel of  the  engine,  to  which  a  rotary  motion  is  to  be 
communicated.  Upon  the  axis  of  this  fly-wheel,  a  small 
toothed  wheel  is  firmly  fixed.  A  second  toothed  wheel 
is  connected  to  the  first,  by  a  loose  crank,  so  as  to  be 
capable  of  revolving  freely  about  it.  This  second  wheel 
is  firmly  fixed  upon  the  end  of  a  connecting  rod,  which  is 
attached,  by  a  joint,  to  the  beam  of  the  engine.  The  two 
wheels  being  in  gear,  it  is  obvious,  that  as  the  beam.  A, 
rises  and  falls,  the  second  wheel,  with  the  assistance  of 
the  fly,  will  revolve  quite  round  the  first  ;  and,  if  the 
num_ber  of  teeth  be  equal,  the  first,  or  sun-wheel,  must 
perform  two  rotations  on  its  axis,  while  the  second,  or 
planet-wheel,  revolves  once  round  it. 

The  necessity  of  this  will  be  more  obvious,  when  we 
consider,  that,  if  one  tooth  of  the  planet-wheel,  were  con- 
nected by  a  joint  to  one  tooth  of  the  sun-wheel,  it  would 
act  as  a  simple  crank,  and  cause  one  revolution.  But  an 
additional  revolution  is  also  necessary,  because,  during 
the  circuit,  all  the  teeth  of  the  planet-wheel  must  act 


INCLINED    WHEEL. EPICYCLOIDAL   WHEEL. 


69 


upon  those  of  the  sun-wheel,  thus  turning  it  round,  as  in 
common  wheel-work. 


Fig.  136. 
C  E 

■      tl 


D         F 

Inclined  Wheel. — In  Fig.  136,  AB,  is  a  wheel,  placed 
obliquely  on  its  axis,  CD.  The  edge,  or  periphery,  of 
this  wheel,  is  received  in  a  notch,  at  B,  of  a  sHding  bar, 
EF.  As  the  wheel  revolves,  the  bar,  EF,  will  move  up 
and  down  once,  during  each  revolution.  This  reciprocal 
motion  may  be  indefinitely  varied,  by  bending  the  edge  of 
the  wheel  into  different  curves  and  angles. 

Epicycloidal  Wheel. — A  very  beautiful  method  of  con- 
verting circular  into  alternate  motion,  or  alternate  into  cir- 
cular, is  shown  in  Fig  137.  AB  is  a  fixed  ring,  or  wheel, 

Fig.  137. 


toothed  on  its  inner  side.  C,  is  a  toothed  wheel,  of  haft 
the  diameter  of  the  ring,  revolving  about  the  centre  of  the 
ring.  While  this  revolution  of  the  wheel,  C ,  is  taking  place. 


70 


ELEMENTS   OF  MACHINERY. 


any  point,  whatever,  on  its  circumference,  will  describe  a 
straight  line,  or  will  pass  and  repass  through  a  diameter 
of  the  circle,  once,  during  each  revolution.  This  is  an 
elegant  appHcation  of  the  law,  that,  if  a  circle  rolls  on  the 
inside  of  another  of  twice  its  diameter,  the  epicycloid  de- 
scribed is  a  straight  line.  In  practice,  a  piston,  rod,  or 
other  reciprocating  part,  may  be  attached  to  any  point 
on  the  circumference  of  the  wheel,  C. 

Rack  and  Segment. — If  an  alternating  motion  is  requir- 
ed, the  velocity  of  which  shall  be  always  equal,  a  rack  is 
best  adapted  to  produce  this  effect.     In  Fig.  138,  AB 

Fig.  138. 


a  a  parallelogram,  having  a  rack  on  two  opposite  sides. 
0,  is  a  half  wheel,  toothed  on  its  curved  side,  and  having 
its  centre  equally  distant  from  the  two  racks.  It  is  ob- 
vious, from  inspection,  that,  as  this  half  wheel  revolves,  its 
teeth  will  act  successively  upon  the  two  racks,  and  cause 
the  parallelogram  to  move  back  and  forwards,  with  a  uni- 
form motion.  The  change,  however,  from  one  direction 
to  the  other,  will  be  nearly  instantaneous,  so  that  this  plan 
will  only  answer  in  machinery  which  is  very  hght,  or  of 
slow  motion.  The  teeth  of  the  half  wheel  must  cover 
somewhat  less  than  half  a  circle,  that  they  may  not  become 
engaged  in  one  rack,  before  they  are  disengaged  from  the 
other. 

Rack  and  Pinion. — Another  contrivance,  which  ren- 
ders the  change  more  gradual,  is  represented  in  Fig.  139. 
AB,  is  a  double  rack,  with  circular  ends,  fixed  to  a  beam, 
capable  of  moving  in  the  direction  of  its  length.  The  rack 
IS  driven  by  a  pinion,  P,  which  is  capable  of  moving  up 
and  down  in  a  groove,  [m?i,]  cut  in  the  cross-piece.  When 
the  pinion  has  moved  the  rack  and  beam,  until  it  comes  ta 


BELT  AND  SEGMENT. ^SCAPEMENTS. 


71 


Fig.  139. 


„  % 

P                      n 

V 

ar 

V»         a 

^u 

the  end,  B,  the  projecting  piece  [a]  meets  the  spring,  [5,] 
and  the  rack  is  pressed  against  the  pinion.  The  pinion, 
then  working  in  the  circular  end  of  the  rack,  will  be  forced 
down  the  groove,  [mn,]  until  it  works  in  the  lower  side  of 
the  rack,  and  moves  the  beam  back  in  theopposite  direction ; 
and,  in  this  way,  the  motion  is  continued.  The  motion 
of  the  pinion  in  the  groove  will  be  diminished,  if,  instead 
of  a  double  rack,  we  use  a  single  row  of  pins,  which  are 
parallel  to  the  axis  of  the  pinion,  as  in  some  of  the  ma- 
chines, called  mangles. 

Belt  and  Segment. — An  alternate  circular  motion  is 
converted  into  an  alternate  rectilinear  motion,  in  fire-en- 
gines, dressing-machines,  &c.,  by  a  belt,  or  chain,  fasten- 
ed to  each  end  of  a  segment,  or  other  portion  of  a  wheel. 
The  two  belts  pass  by  each  other,  and  are  attached  to  the 
opposite  ends  of  an  alternating  part.  When  the  segment 
turns,  in  either  direction,  it  draws  after  it  the  alternating 
par^,,  in  a  straight  line.      [Fig.  140.] 

Fig.  140. 


Scapements.  —  In   clocks  and  watches,  an  alternating 
motion  is  produced  in  the  pendulum  and  balance-wheel, 


72 


ELEMENTS  OF  MACHINERY. 


by  means  of  the  mechanism  called  a  scapement.  In  the 
more  simple  scapements,  two  teeth,  called  pallets,  are 
made  to  vibrate  on  a  common  axis.  They  are  connect- 
ed with  a  toothed  wheel,  in  such  a  manner,  that  one  pallet 
enters  between  the  teeth  of  the  wheel,  whenever  the  other 
is  thrown  out  of  their  reach.  As  the  wheel  revolves,  its 
teeth  successively  impinge  against  one  or  the  other  of 
these  pallets,  and,  by  causing  them  successively  to  escape, 
communicate  to  their  axis  a  vibrating,  or  alternate,  motion. 
The  crutch  scapement,  [Fig.  141,]  is  an  arch,  situated  in 
the  same  plane  with  the  scape-wheel,  and  parallel  to  the 
plane  in  which  the  pendulum  vibrates.  Its  pallets  suc- 
cessively enter  and  escape  from  the  teeth  of  the  wheel, 
and  receive  from  it  a  vibrating  motion.  In  the  old,  or  com- 
mon, watch  scapement,  [Fig.  142,]  a  contrate,  or  crown, 
wheel  is  used  as  the  scape-wheel,  and  the  pallets  [a  and 
b]  are  placed  upon  the  axis  of  the  balance-wheel,  so  as  to 
meet  the  teeth,  successively,  on  opposite  sides  of  the  cir- 
cumference of  the  scape-wheel.  A  variety  of  other  more 
complicated  forms  of  the  scapement  are  also  in  use. 


Fig.  141. 


Fig.  142. 


BAND. RACK.  73 


CONTINUED  RECTILINEAR  MOTION. 

A  long-continued  rectilinear  motion  is  not  to  be  pro 
duced  in  the  parts  of  a  machine,  except  so  far  as  it  par- 
takes of  the  nature  of  a  rotary,  or  a  reciprocating,  motion. 
Thus,  a  band,  passing  round  pullies,  is  a  modification  of 
rotary  motion,  and  a  rack,  which  is  obliged  to  return  at 
intervals,  has  a  reciprocatmg  motion.  But,  to  a  certain 
extent,  the  motions  of  both  may  be  regarded  as  conftti- 
iiously  rectilinear. 

Band. — If  it  is  required  to  produce  motion,  in  a  right 
line,  which  shall  be  always  in  one  direction,  as,  for  exam- 
ple, in  the  feeding  parts  of  machines,  a  band,  passing  round 
pullies  or  drums,  is  the  method  most  commonly  practised, 
as  in  Fig.  105.  If  a  precise  velocity  is  required,  the  band 
may  be  perforated  with  holes,  and  received  upon  short 
pins,  at  the  circumference  of  the  wheels  ;  or  the  rag-wheel 
and  chain,  represented  in  Fig.  107,  may  be  substituted. 

Rack. — If  a  slow  rectilinear  motion  is  required  only 
for  limited  times,  such  a  mechanism  may  be  used,  as  will 
permit  the  moving  part  to  retrace  its  own  path,  at  inter- 
vals, and  regain  its  original  situation.      [Fig.  143.]     A 


rack,  which  is  a  straight  bar,  having  teeth  on  one  side,  will 
move  in  this  manner,  if  it  be  acted  on  by  a  toothed  wheel, 
or  by  a  perpetual  screw.  If  the  thread  of  a  perpetual 
screw  be  formed  of  different  obliquity,  in  different  parts 
of  its  circumference,  the  progressive  velocity  of  the  rack 
will  be  unequal,  instead  of  being  uniform.  And,  if  a  part 
of  the  thread  be  in  a  plane,  at  right  angles  with  the  axis 
of  the  screw,  the  rack  will  be  at  rest,  while  that  part  of 
the  screw  revolves  in  contact  with  it. 


XII. 


74 


ELEMENTS  OF  MACHINERY. 


Universal  Lever. — A  rack  is  also  propelled,  by  means 
of  a  catch,  or  dog,  connected  with  some  part  of  the  ma- 
chine, which  has  an  alternating  motion.  The  catch  caus- 
es the  rack  to  advance,  the  length  of  one  tooth,  at  each 
stroke  of  the  alternating  part.  The  universal  lever,  some- 
times called  the  lever  of  La  Garousse,  consists  of  a  bar 
moving  upon  a  centre,  and  havmg  a  movable  catch,  or 
hook,  attached  to  each  side,  and  acting  upon  the  oblique 
te^h  of  a  double  rack,  or  of  a  ratchet-wheel,  so  that  the 
alternating  motion  of  the  bar  causes  a  progressive  motion 
of  the  rack,  or  wheel.  [Fig.  144.] 
Fig.  144. 


Screw. — A  common  screw  is  often  made  use  of,  to 
produce  rectilinear  movements,  when  the  motion  is  in- 
tended to  be  very  slow,  or  when  great  power  is  required. 

Change  of  Direction. — A  change,  from  one  path,  or 
direction,  to  another,  forming  an  angle  with  it,  may  be 
produced,  by  several  of  the  mechanical  powders.  Thus,  a 
cord,  passing  over  a  pulley,  may  change  a  perpendicular 
to  a  horizontal  motion,  as  at  P,  [Fig.  159,]  or  to  one  at 
any  other  angle  required.  A  bent  lever,  like  that  repre- 
sented by  y  z,  in  PI.  III.,  produces  the  same  effect,  pro- 
vided the  moving  parts  are  confined,  by  guides,  to  their 
respective  paths.  An  inclined  plane,  also,  if  it  moves 
through  the  length  of  one  side  of  a  parallelogram,  will 
cause  another  body  to  move  through  the  length  of  the 
contiguous  side,  at  right  angles.  This  method,  however, 
is  attended  with  much  friction. 

Toggle  Joint. — The  knee-joint^  ccmmonly  called,  in 


OP  ENGAGING  AND  DISENGAGING  MACHINERY.      75 

this  country,  toggle-joint,  affords  a  very  useful  mode  of 
converting  velocity  into  power,  the  motion  produced  be- 
ing nearly  at  right  angles  with  the  direction  of  the  force. 
Its  operation  is  seen  in  the  iron  joints  which  are  used,  to 
uphold  the  tops  of  chaises.  It  is  also  introduced  into 
various  modifications  of  the  printing  press,  in  order  to 
obtain  the  greatest  power,  at  the  moment  of  the  impres- 
sion. It  consists  of  two  rods,  or  bars,  connected  by  a 
joint,  and  increases  rapidly  in  power,  as  the  two  rods  ap- 
proach to  the  direction  of  a  straight  line.*  In  Fig.  145, 
a  moving  force,  applied  in  the  direction  CD,  acts  with 
great  and  constantly  increasing  power,  to  separate  the 
parts,  A  and  B. 


•  C 


OF  ENGAGING  AND  DISENGAGING  MACHINERY. 

In  many  cases,  particularly  where  numerous  machines 
are  propelled  by  a  common  power,  it  is  important  to  pos- 
sess the  means  of  stopping  any  one  of  them,  at  pleasure, 
and  of  restoring  its  motion,  without  interfering  with  the 
rest.  To  produce  this  effect,  a  great  variety  of  combi 
nations  have  been  invented,  under  the  name  of  couplings. 
These,  in  most  instances,  are  sHding  boxes,  which  move 
longitudinally  upon  shafts  or  axles,  and  serve  to  engage, 
or  lock,  a  shaft  which  is  at  rest,  with  one  which  is  in  mo- 
tion ;  so  as  practically  to  convert  the  two  into  one,  until 

*  An  investigation  of  the  power  of  this  combination,  is  given  hy  the 
late  Professor  Fisher,  in  Silliman's  Journal,  \ol.  iii.  p.  320. 


76  ELEMENTS   OF  MACHINERY. 

they  are  again  unlocked.  Couplings  are  sometimes  pro- 
vided with  clutches,  or  glands,  which  are  projecting  teeth, 
intended  to  catch  on  other  teeth,  or  levers,  and  thus  lock 
the  shafts  together.  Sometimes  they  have  bayonets,  or 
pins,  adapted  to  enter  holes.  Sometimes,  the  connexion 
is  produced  by  friction  alone,  by  pressing  together  sur- 
faces, which  are  either  flat,  or  conical.  Sometimes,  also, 
wheels  are  thrown  into^  and  out  of,  gear,  which  is  done, 
by  causing  wheels  to  shde  in  the  direction  of  their  axles, 
or,  in  some  cases,  by  elevating  and  depressing  the  axle 
itself.  These  methods,  however,  are  difficult  and  un- 
safe. The  live  and  dead  pulley  afibrd,  perhaps,  the  sim- 
plest mode  of  engagement.  They  consist  of  two  paral- 
lel band-wheels,  on  the  same  axle,  one  of  which  is  fast, 
and  the  other  loose,  or  capable  of  turning  without  the 
axle.  The  band,  which  communicates  the  power,  is 
placed  upon  the  loose  pulley,  when  it  is  desired  to  stop 
the  machine,  and  upon  the  fast  pulley,  when  it  is  intend- 
ed to  set  the  machine  in  motion.  A  common  band  may, 
also,  be  made  to  admit  of  motion  or  rest,  according  as  it 
is  rendered  tense,  or  loose,  by  a  tightening  wheel,  pressed 
against  hs  side  by  a  lever. 

OF  EQUALIZING  MOTION. 

In  most  machines,  both  the  moving  force,  and  the  re- 
sistance to  be  overcome,  are  liable  to  fluctuations  of  in- 
tensity, at  different  times.  As  such  variations  influence 
both  the  safety  and  efficiency  of  machines,  it  is  necessa- 
ry to  provide  against  them,  by  some  appendage,  which 
shall  equalize  either  the  supply,  or  the  distribution,  of  the 
power. 

Governor. — The  name  of  governor  has  been  given  to 
an  ingenious  piece  of  mechanism,  which  has  been  intro- 
duced, to  regulate  the  supply  of  steam,  in  steam-engines, 
and  of  water,  in  water-mills,  so  as  to  render  the  power 
equable,  and  proportionate  to  the  resistance  to  be  sur- 
mounted. It  is  represented  in  Fig.  146,  on  the  opposite 
page.  x\B,  and  AC,  are  two  levers,  or  arms,  loaded  with 
heavy  balls,  at  their  extremities,  B  and  C,  and  suspended, 
by  a  joint,  at  A,  upon  the  upper  extremity  of  a  revolv- 


GOVERNOR.  77 


ing  shau,  AD.  At  [a,]  is  a  collar,  or  sliding  box,  cou- 
nected  to  the  levers,  by  the  rods  [a6,  and  ac,]  with 
joints  at  their  extremities.  It  follows,  that  when  the 
weights,  B  and  C,  diverge,  the  collar  [a]  will  move  up- 
ward, on  the  shaft.  AD,  and  vice  versa.  The  governor, 
thus  constructed,  is  attached  to  some  revolving  part  of  the 
machine.  In  this  state,  if  it  turns  too  rapidly,  the  balls, 
B  and  C,  move  outwards,  by  their  centrifugal  force,  and 
draw  upward  the  collar,  [a.]  If,  on  the  other  hand,  the 
speed  diminishes,  the  balls  are  allowed  to  subside,  and  the 
collar  moves  down  upon  the  shaft.  In  the  steam-engine, 
the  collar  has  a  circular  groove,  which  receives  the  end  of 
a  forked  lever.  As  the  collar  rises  and  falls,  this  lever 
turns  upon  its  fulcrum,  and  acts,  remotely,  to  open  or  close 
a  throttle-valve,  which  is  placed  in  the  main  steam-pipe.* 
Whenever,  therefore,  the  machine  moves  too  rapidly,  the 
balls  recede  from  the  centre,  the  collar  rises,  the  lever 
moves  the  valve,  and,  by  partially  closing  the  pipe,  di- 
minishes the  quantity  of  steam  admitted  from  the  boiler. 
If  the  machine  moves  too  slowly,  the  reverse  takes  place, 
and  a  larger  amount  of  steam  is  admitted. 

In  water-wheels,  where  a  greater  power  is  necessary 
to  control  the  supply  of  water,  the  governor  is  usually 
connected  to  the  sluice-gate,  by  the  intervention  of  wheel- 
work.      This  may  be  done  in  several  ways,  one  of  which 

*  For  a  further  account  of  the  governor,  see  the  article,  Steam  Eiu 
gine. 

7* 


78  ELEMENTS   OP  MACHINERY. 

IS  as  follows.  The  lower  part  of  the  shaft,  AD,  carries 
a  wheel  at  D,  acting  upon  two  others  beneath  it,  M  and 
N.  While  the  machinery  moves  with  its  proper  speed, 
the  wheels,  M  and  N,  are  both  unlocked,  and  turn  loosely 
round  their  axles,  and  the  gate  is  stationary.  But,  when 
the  velocity  increases  or  diminishes,  the  collar  [a]  rises  or 
falls,  and,  by  means  of  a  cam,  acts  upon  a  lever  above  it, 
or  upon  another  below  it,  so  as  to  lock  one  of  the  wheels, 
M  or  N,  by  moving  a  clutch  situated  at  [c?.]  These 
wheels,  being  upon  a  common  axle,  are  capable  of  turning 
this  axle  different  ways.  When,  therefore,  one  wheel  is 
locked  to  the  axle,  it  acts  by  turning  a  perpetual  screw, 
to  open  the  sluice  gate.  When  the  other  is  locked,  the 
axle  and  the  screw  turn  in  the  opposite  direction,  and 
partially  close  the  gate. 

The  foregoing  are  some,  out  of  various,  modes  in  which 
the  governor  is  appHed.  In  windmills,  it  is  so  adapted  as 
to  increase  the  feeding,  or  supply  of  corn,  when  the  mill 
goes  too  fast,  and  also  to  vary  the  distance  of  the  mill- 
stones from  each  other,  if  necessary.  It  has  also  been 
applied  to  clothe  and  unclothe  the  sails,  in  proportion  to 
the  strength  of  the  wind. 

Fly  Wheel. — It  is  an  object  of  great  importance,  in 
machines,  to  have  the  means  of  accumulating  power,  when 
the  moving  force  is  in  excess,  and  of  expending  it,  when 
the  moving  force  operates  more  feebly,  or  the  resistance 
increases.  This  equahzalion  of  motion  is  obtained,  by 
what  is  called  a  fly,  which  is  generally  made  in  the  form 
of  a  heavy  wheel,  though,  sometimes,  in  the  form  of  arms, 
or  crossbars,  with  weights  at  their  extremities.  A  fly 
being  made  to  revolve  about  its  axis,  keeps  up  the  force, 
by  its  own  inertia,  and  distributes  it,  in  all  parts  of  its  rev- 
olution. If  the  moving  power  slackens,  it  impels  the 
machine  forward  ;  and  if  the  power  tends  to  move  the 
machine  too  fast,  it  keeps  it  back. 

Fly-wheels  are  capable  of  accumulating  power  to  a 
great  extent.  A  small  force,  continually  applied  to  the 
surface  of  a  heavy  revolving  wheel,  will  eccelerate  its  ve- 
locity, till  it  shall  be  equal  to  that  of  a  musket-ball,  and 
ts  momeatum   almost  irresistible.      Fjy- wheels,  to  act 


FRICTION.  79 

i^ith  th<y  greatesv  efficacy,  should  be  made  with  the  least 
possible  surface,  that  their  motion  may  not  be  impeded, 
by  the  resistance  of  the  air.  They  should  be  made  of 
iron,  and,  if  they  cannot  be  cast  in  one  piece,  they  should 
be  firmly  hooped,  or  bolted  together,  that  the  parts  may 
not  separate,  by  their  centrifugal  force.  Fatal  accidents 
have  occurred  from  the  bursting  of  large  stones,  used  as 
flies,  or  as  grindstones,  in  cutlery  works,  their  velocity, 
and  centrifugal  force  being  so  great,  as  to  overcome  their 
cohesive  attraction,  and  to  project  the  parts  to  a  distance, 
with  great  violence. 

Beside  the  modes  already  described,  other  methods 
are  employed,  to  retard  and  equalize  the  velocity  of  ma- 
chinery. A  kind  of  fly  is  used,  in  music  boxes,  and  in 
the  striking  part  of  clocks,  in  which  the  broad  surface  of 
vanes,  upon  the  circumference  of  a  wheel,  is  made  to  act 
against  the  air,  until  the  resistance  becomes  equal  to  the 
propelling  force,  so  that  the  velocity  can  increase  no  fur- 
ther, but  becomes  uniform.  Pendulums  and  balances, 
acted  on  through  the  difierent  kinds  of  scapements,  are 
also  means  of  equalizing  motion. 

FRICTION. 

A  part  of  the  force,  by  which  machines  are  moved,  is 
expended  in  overcoming  their  friction.  Hence  it  is  desir- 
able to  obviate,  as  far  as  possible,  this  kind  of  resistance. 
Friction  is  supposed  to  arise,  chiefly,  from  the  roughness 
and  inequality  of  the  surfaces  of  bodies.  No  pohsh  can 
be  given  to  a  surface,  mechanically,  so  fine,  as  to  render 
it  perfectly  smooth.  When  surfaces  move  over  each 
other,  a  certain  force  is  necessary  to  disengage  the  minute 
asperities  of  one  surface  from  those  of  the  other,  either 
by  causing  them  to  rise  over  each  other,  or  by  bending 
or  breaking  them  down. 

Friction  is  increased,  by  the  roughness  of  bodies,  and, 
also,  by  the  force  with  which  they  are  pressed  together. 
But  it  is  very  little  afiected  by  the  extent  of  the  surfaces 
in  contact.  It  is  greatest,  at  the  moment  when  motion 
begins.  It  does  not,  however,  change  afterwards  as  the 
velocity  changes,  but  continues  to  retard,  with  a  uniform 


80  ELEMENTS   OF  MACHINERY. 

force,  whether  the  motion  performed  be  slow,  or  i-apm. 
There  are  several  points,  in  regard  to  friction,  upon  which 
writers  are  not  agreed. 

Friction  in  machinery  is  to  be  diminished,  by  making 
the  surfaces,  which  rub  upon  each  other,  as  smooth  as  pos- 
sible, and  by  covering  them  w  th  some  unctuous  substance. 
Black  lead,  in  fine  powder,  is  sometimes  interposed  be- 
tween surfaces,  to  diminish  friction,  and  soapstone,  applied 
in  the  same  manner,  is  still  more  useful.  It  is  supposed, 
Dy  some,  that  different  metals,  moving  upon  each  other, 
occasion  less  friction,  than  surfaces  of  the  same  metal. 
But  the  most  important  mode  of  diminishing  friction  is,  to 
employ  a  rolling  or  turning  motion,  instead  of  a  sliding 
motion,  in  all  cases  where  it  is  practicable  ;  and,  by  sim- 
plicity of  construction,  to  avoid  all  unnecessary  contact  of 
moving  surfaces. 

Remarks. — In  the  construction  of  machines,  no  subject 
is  more  deserving  of  attention,  than  simpHcity  of  parts  and 
structure.     The  more  complex  machines  are,  the  more 
expensiva  they  are  to  erect,  the  more  liable  to  get  out  of 
order,  and  the  more  difficult  to  repair.     An  increased 
expenditure  of  power  is  also  occasioned,  by  their  friction. 
A  complex  machine  may  evince  great  ingenuity  on  the 
part  of  the  inventor,  and  may  have  cost  much  labor  and 
science  to  complete  it.     Yet  it  is  sure  to  be  superseded, 
the  moment  that  a  more  simple,  cheap,  or  expeditious 
way  of  attaining  the  same  object  is  discovered.     The  im 
provement  of  the  mechanist,  or  engineer,  more  frequent 
ly  consists  in  the  simplification  of  his  means,  than  it  does 
in  the  construction  of  complex  and  difficult  pieces  of  work 
manship. 

Works  3f  Reference. — Buchanan,  on  Mill  Work,  and  other 
Machinery,  2  vols.  8vo.  1823  ; — Robison's  Mechanical  Philosophy, 
vol.  ii.  p.  181  ; — Nicholson's  Operative  Mechanic,  8vo.  1825  ; — 
Gregory's  Mechanics,  1826  ; — Brewster's  edition  of  Ferguson's 
Mechanics,  1823  , — Borgnis,  Mechanique  Appliquee  aux  Arts,  4to 
Paris,  1818,  Tom.  3,  Composition  des  Machines; — Lanz  et  Bet 
TANCOURT,  sur  1(1  ComposHion  des  Machines,  Paris,  4to.  1819  ;— 
IIachette,  Traite  Elementaire  des  Machines  ; — Leupold,  TJie 
atrum  Machinarum  Universale,  7  vols,  folio,  Loipsic,  1724  to  1774 


MOVING  FORCES  USED  IN  THE  ARTS.  81 


CHAPTER  XVI. 

OF  THE  MOVING  FORCES  USED  IN  THE  ARTS. 

Sources  of  Power,  Vehicles  of  Power.  Animal  Power,  Men,  Hors 
es.  Water  Power,  -Overshot  Wheel,  Chain  Wheel,  Undershot 
Wheel,  Back  Water,  Besant's  Wheel,  Lambert's  Wheel,  Breast 
Wheel,  Horizontal  Wheel,  Barker's  Mill.  Wind  Power,  Vertical 
Windmill,  Adjustment  of  Sails,  Horizontal  Windmill.  Steam  Pow- 
er, Steam,  Applications  of  Steam,  By  Condensation,  By  Generation, 
By  Expansion,  The  Steam  Engine,  Boiler,  Appendages,  Engine,  Non- 
condensing  Engine,  Condensing  Engines,  Description,  Expansion  En- 
gines, Condenser,  Valves,  Pistons,  Parallel  Motion,  Locomotive  En- 
gine, Power  of  the  Steam  Engine,  Projected  Improvements,  Rotative 

^  Engines,  Use  of  Steam  at  High  Temperatures,  Use  of  Vapors  of 
Low  Temperature,  Gas  Engines,  Steam  Carriages,  Steam  Gun. 
Gunpowder ,  Manufacture,  Detonation,  Force,  Properties  of  a  Gun, 
Blasting,  Magnetic  Engines. 

Sources  of  Poicer. — It  is  the  office  of  machines,  to  re- 
ceive and  distribute  motion,  derived  from  an  external 
agent,  since  no  machine  is  capable  of  generating  motion, 
or  moving  power,  within  itself.  The  sources  from  which 
the  moving  power,  apphed  to  machinery,  is  obtained,  are 
various,  according  to  the  nature  of  the  object,  and  the 
amount  of  force,  which  is  required.  Men  and  animals, 
water,  wind,  steam,  and  gunpowder,  are  the  principal 
agents,  employed  as  first  movers  in  the  arts.  Their  pow- 
er may  be  ultimately  resolved  into  those  of  muscular  en- 
ergy, gravity,  heat,  and  chemical  affinity.  But,  although 
these  are  the  sources  of  all  the  important  force,  which  is 
artificially  employed,  in  moving  large  masses  of  matter, 
yet,  certain  other  agents  are  also  capable  of  producing 
motion,  upon  a  more  limited  scale  ;  such  as  magnetism, 
electricity,  capillary  attraction,  &c. 

Vehicles  of  Poicer. — Besides  the  original  forces  which 
have  been  mentioned,  there  are  certain  intermediate  agents, 
which  serve  to  accumulate  and  transmit  power,  after  the 
first  mover  has  ceased  to  operate.  These  agents  com- 
monly act,  either  by  their  elasticity,  their  gravity,  or  their 
inertia.      Springs,  and  compressed  air,  are  examples  of 


82       MOVING  FORCES  USED  IN  THE  ARTS. 

vehicles,  acting  by  their  elasticity,  and  their  usefulness 
continues,  only,  till  they  have  recovered  the  situation  from 
which  they  were  disturbed  by  another  force.  In  like 
manner,  a  weight,  acting  by  its  gravity  on  an  axle,  or 
wheel,  prolongs,  for  a  season,  the  influence  of  the  power, 
by  which  it  was  w^ound  up.  Fly-wheels  are  also  vehi- 
cles which  serve,  by  their  inertia,  to  continue  the  action 
of  a  force  while  it  intermits.  Vehicles  of  power  are 
highly  useful,  in  equalizing  the  irregularities  which  are  in- 
cident to  prime  movers,  in  prolonging  their  action  through 
convenient  periods  of  time,  and  in  multiplying  the  modes 
of  their  application. 

A  fundamental  distinction  among  mechanical  agents, 
both  original  and  secondary,  consists  in  this  ;  that,  in  some, 
the  intensity  of  their  action,  or  the  acceleration  they  prc^ 
duce  in  a  given  time,  is  the  same,  whether  the  body  acted 
upon  be  at  rest,  or  in  motion  ;  in  others,  it  is  greatest, 
when  the  body  acted  on  is  at  rest,  and  becomes  less,  as 
its  velocity  increases.  Gravity  is  the  only  force,  which 
is  certainly  known  to  act,  with  equal  intensity,  on  bodies 
m  motion,  and  at  rest ;  though  magnetism,  probably,  pos- 
sesses the  same  property.  Every  other  important  power 
acts  more  forcibly  on  a  body  at  rest,  than  on  one  which 
has  already  acquired  motion,  in  the  direction  in  which  it 
acts.*  This  happens  with  the  strength  of  animals,  the 
impulse  of  fluids,  and  the  elasticity  of  springs. 

ANIMAL   POWER. 

Muscular  energy  is  exerted  through  the  contraction  of 
the  fibres  which  constitute  animal  muscles.  The  bones 
act  as  levers,  to  facihtate  and  direct  the  application  of  this 
force,  the  muscles  operating  on  them,  through  the  medi- 
um of  tendons,  or  otherwise.  Muscular  power  is  much 
greater  in  some  animals,  than  it  is  in  man,  owing  to  their 
size,  or  more  active  mode  of  life.  It  is  greatest  in  beasts 
of  prey. 

jyien. — The  power  of  a  man  to  produce  motion,  in 
weights  or  obstacles,  varies,  according  to  the  mode  in 
which  he.apphes  his  force,  and  the  number  of  muscles 

*  See  Playfau's  Outlines  of  Natural  Philosophy,  vol.  i.  p.  107. 


MEN.  83 

fvhich  are  brought  into  action.  In  the  operation  of  turn- 
ing a  crank,  a  man's  power  changes,  in  every  part  of  the 
circle  which  the  handle  describes.  It  is  greatest,  when 
he  pulls  the  handle  upward,  from  the  height  of  his  knees  ; 
next  greatest,  when  he  pushes  it  down,  on  the  opposite 
side  ;  though,  here,  the  power  cannot  exceed  the  weight 
of  his  body,  and  is,  therefore,  less  than  can  be  exerted, 
iTi  pulling  upward.  The  weakest  points,  are  at  the  top 
and  bottom  of  the  circle,  where  the  handle  is  pushed,  or 
drawn,  horizontally. 

If  a  windlass  be  provided  with  two  cranks,  placed  at 
right  angles  with  each  other,  two  men  will  perform  much 
more  work,  than  they  could,  if  the  cranks  were  discon- 
nected ;  because,  at  the  moment  one  puts  forth  his  strength 
to  the  least  advantage,  the  other  is  exerting  his  with  the 
greatest  efiect. 

The  mode  i#  which  a  man  can  exert  the  greatest  active 
strength,  is  in  pulling  upward  from  his  feet ;  because  the 
strong  muscles  of  the  back,  as  well  as  those  of  the  upper 
and  lower  extremities,  are  then  brought  advantageously 
into  action,  and  the  bones  are  favorably  situated,  by  the 
fulcra  of  the  levers  being  near  to  the  resistance.  Hence, 
the  action  of  rowing  is  one  of  the  most  advantageous 
modes  of  muscular  exertion  ;  and  no  method  which  has 
been  devised  for  propelling  boats,  by  the  labor  of  men, 
has  hitherto  superseded  it. 

According  to  Mr.  Buchanan,  the  comparative  effect 
produced,  by  different  modes  of  applying  the  force  of  a 
man,  is  nearly  as  follows.  In  the  action  of  turning  a 
crank,  his  force  may  be  represented  by  the  number  seven- 
teen. In  working  at  a  pump,  by  twenty-nine.  In  pul- 
ling downward,  as  in  the  action  of  ringing  a  bell,  by  thirty- 
nine.  And  in  pulling  upward  from  the  feet,  as  in  rowing, 
by  forty- one.* 

In  estimating  the  different  applications  of  animal  force, 
we  must  take  into  consideration,  not  only  the  resistance 
they  can  overcome,  but  the  velocity  with  which  they 
move,  and  the  length  of  time,  for  which  they  can  be  con- 

*  See  Brewster's  edition  of  Ferguson's  Mechanics,  vol.  ii.  p.  9 
The  whole  numbers  are  1742,  2856,  3883,  and  4095. 


84  MOVING  FORCES   USED  IN  THE  ARTS 

tinned.  Violent  efforts  are  not  true  specimens  of  a  n^ian  a 
labor,  since  they  can  be  exerted  for  a  short  time  only. 
A  moderate  computation  of  an  ordinary  man's  uniform 
strength  is,  that  he  can  raise  a  weight  of  ten  pounds,  to 
the  height  of  ten  feet,  once  in  a  second,  and  continue  this 
labor,  for  ten  hours  in  the  day.*  This  is  supposing  him 
to  use  his  force,  under  common  mechanical  advantages, 
and  without  any  deduction  for  friction. 

Horses. — Horses  are  often  employed  as  movers  of 
machinery,  by  their  draught.  A  horse  draws  with  great- 
est advantage,  when  the  line  of  draught  is  not  horizon- 
tal, but  inclines  upward,  making  a  small  angle  with  the 
horizontal  plane,  as  already  stated,  page  18.  The  force 
of  a  horse  diminishes,  as  his  speed  increases.  The  fol- 
lowing proportions  are  given  by  Professor  Leslie,  for  the 
force  of  the  horse,  employed  under  different  velocities. 
If  his  force,  when  moving  at  the  rate  (#  two  miles  per 
hour,  is  represented  by  the  number  one  hundred,  his  force, 
at  three  miles  per  hour,  will  be  eighty-one  ;  at  four  miles 
per  hour,  sixty-four  ;  at  five  miles,  forty-nine  ;  and,  at 
six  miles,  thirty-six.  These  results  are  confirmed,  very 
nearly,  by  the  observations  of  Mr.  Wood.f  In  this  way, 
the  force  of  a  horse  continues  to  diminish,  till  he  attains 
his  greatest  speed,  when  he  can  barely  carry  his  own 
weight. 

Various  estimates  have  been  made  of  a  horse's  pow- 
er, by  Desaguhers,  Smeaton,  and  others  ;  but  the  esti- 
mate, now  generally  adopted,  as  a  standard  for  measuring 
the  power  of  steam-engines,  is  that  of  Mr.  Watt,  whose 
computation  is  about  the  average  of  those  given  by  the 
other  writers.  The  measure  of  a  horse's  power,  accord- 
ing to  Mr.  Watt,  is,  that  he  can  raise  a  weight  of  thirty- 
three  thousand  pounds,  to  the  height  of  one  foot,  in  a 
minute. 

In  comparing  the  strength  of  horses,  with  that  of  men, 
.^f.saguliers  and  Smeaton  consider  the  force  of  one  horse 

be  equal  to  that  of  five  men  ;  but  writers  differ  on  this 
*  ibject. 

*  Young's  Lectures  on  Natural  Philosophy,  vol.  i.  p.  131 
t  Treatise  on  Rail  Roads,  p.  239. 


WATER-POWER. OVERS  HOT- WHEEL.  86 

When  a  horse  draws  in  a  mill,  or  engine  of  any  kind, 
he  is  commonly  made  to  move  in  a  circle,  drawing  after 
him  the  end  of  a  lever,  which  projects,  hke  a  radius,  from 
a  vertical  shaft.  Care  should  be  taken  that  the  horse- 
walk,  or  circlcy  in  which  he  moves,  be  large  enough  in 
diameter  ;  for,  since  the  horse  is  continually  obliged  to 
move  in  an  oblique  direction,  and  to  advance  sideways, 
as  well  as  forward,  his  labor  becomes  more  fatiguing,  in 
proportion  as  the  circle,  in  which  he  moves,  becomes 
smaller. 

In  some  ferry-boats  and  machines,  horses  are  placed 
on  a  revolving  platform,  which  passes  backyvard,  under 
the  feet,  whenever  the  horse  exerts  his  strength,  in  draw- 
ing against  a  fixed  resistance  ;  so  that  the  horse  propels 
the  machinery,  without  moving  from  his  place.  A  horse 
may  act  within  still  narrower  limits,  if  he  is  made  to  stand 
on  the  circumference  of  a  large  vertical  wheel,  or  upon 
a  bridge,  supported  by  endless  chains,  which  pass  round 
two  drums,  and  are  otherwise  supported  by  friction  wheels. 
Various  other  methods  have  been  practised,  for  applying 
the  force  of  animals  ;  but  most  of  them  are  attended  whh 
great  loss  of  power,  either  from  friction,  or  from  the  un- 
favorable position  of  the  animal. 

WATER-POWER. 

Water  and  wind,  considered  as  prime  movers,  are  ap- 
plications of  the  force  of  gravity  ;  since,  without  gravity, 
there  would  be  neither  wind,  nor  currents  of  water.  The 
force  of  water  is,  generally,  applied  to  the  circumference 
of  wheels,  which  it  causes  to  revolve,  either  by  its  weight, 
by  its  lateral  impulse,  or  by  both,  conjointly.  Water- 
wheels  are  generally  used  in  one  of  three  forms.  These 
are,  the  over  shot-wheel^  in  which  the  water  descends  from 
the  top  of  the  wheel  to  the  bottom  ;  the  breast-ioheel,  in 
which  it  is  received  at  about  half  the  height  of  the  wheel ; 
and  the  undershot-wheel^  where  it  acts  by  the  impulse  of 
a  current,  flowing  under  the  wheel.  The  overshot  wheel 
is  the  most  powerful  kind,  and  is  always  to  be  employed, 
where  a  sufficient  fall  of  water  can  be  obtained. 

Overshot  Wheel. — This  is  a  wheel,  or  drum,  the  cir- 
II.  8  XII- 


86  MOVING   FORCES   USED   IN   THE  ARTS. 

cumference  of  which  is  occupied  by  a  series  of  cavities, 
commonly  called  buckets,  into  which  the  water  is  deliv- 
ered from  one,  or  more,  spouts,  at  the  top  of  the  wheel. 
By  inspecting  Fig.  147,  it  will  be  seen,  that  the  buckets 

Fiff.  147. 


W: 
W 


on  one  side  of  the  wheel  are  erect,  and  will,  consequently, 
become  loaded  with  water  ;  while  those  on  the  other  side 
are  inverted,  and,  of  course,  empty.  It  follows,  that  the 
loaded  side  will  always  preponderate,  and,  by  descending, 
will  cause  the  wheel  to  revolve. 

If  it  were  possible,  says  Dr.  Robison,*  to  construct 
tho  buckets  in  such  a  manner,  as  to  remain  completely 
^lled  with  water,  till  they  came  to  the  bottom  of  the  wheel, 
the  pressure,  with  which  the  water  urges  the  wheel  round 
its  axis,  would  be  the  same,  as  if  the  extremity  of  the 
horizontal  radius  were  continually  loaded  wuth  a  quantity 
of  water,  sufficient  to  fill  a  square  pipe,  whose  section  is 
equal  to  that  of  the  bucket,  and  whose  length  is  the  diam- 
eter of  the  wheel.  But  such  a  state  of  things  is  impossi- 
ble ;  and,  if  a  bucket  be  full,  while  at  top,  it  will  begin  to 
lose  water,  as  soon  as  it  turns  into  an  oblique  position, 
and  must  continue  to  do  so,  till  it  reaches  the  bottom. 

The  attention  of  engineers  has  been  directed  to  giving 
the  buckets  such  a  form,  as  will  enable  them  to  retain  the 
water,  for  the  longest  time,  on  the  circumference  of  the 
wheel.  The  form  represented  in  Fig.  148,  on  page  87, 
answers  this  purpose  tolerably  well,  and,  from  its  simplici- 
ty, is  the  one  most  commonly  used  ;  but  it  may  be  im- 
proved still  further,  by  giving  an  additional  incfination, 

*  Mechanical  Philosophy,  vol.  ii.  p.  592. 


OVERSHOT-WHEEL.  87 

Fig.  148.  Fig.  149. 


\ 


.iiward,  to  the  outer  edge  of  the  bucket,  as  seen  in  Fig. 
149.  '  As  the  best  economy  of  the  water-power  requires 
that  the  buckets  should  not  be  completely  filled,  the  form, 
here  represented,  will  retain  the  water,  until  it  has  de- 
scended low  on  the  wheel.  To  promote  this  object  still 
further,  Mr.  Burns  has  divided  the  bucket  by  a  partition, 
which  is  parallel  to  the  rim  of  the  wheel,  constitutmg  one 
bucket  within  another.  In  this  mode  of  construction,  the 
water  does  not  enter  with  the  same  facihty,  but  is  longer 
in  escaping.* 

In  order  to  prevent  the  inertia  of  the  water,  when  it  is 
first  laid  upon  the  buckets,  from  impeding  the  motion  of 
the  wheel,  it  is  desirable  that  the  water,  when  it  enters, 
should  have  a  velocity  corresponding,  as  nearly  as  possi- 
ble, to  that  with  which  the  wheel  is  revolving.  And,  as 
we  cannot  give  to  the  water,  the  direction  of  a  tangent  to 
the  wheel,  the  velocity,  w^ith  which  it  is  delivered  on  the 
wd:ieel,  must  be  so  much  greater  than  the  intended  veloci- 
ty of  the  rim,  that  it  shall  be  equal  to  it,  when  it  is  esti- 
mated in  the  direction  of  a  tangent.  To  facilitate,  as 
much  as  possible,  the  entrance  of  the  water,  it  is  common 
to  deliver  the  w^ater  through  an  aperture,  w^hich  is  divided 
by  thin  plates  of  board,  or  metal,  placed  in  an  oblique 
position,  so  as  to  direct  the  stream  of  water  into  the 
buckets,  in  the  most  perfect  manner,  as  represented  in 
Fig.  152,  on  page  93.  In  order  to  detain  the  water,  as 
long  as  possible,  the  lower  part  of  the  wheel  is  often  made 
to  revolve  in  a  concave  cavity,  just  large  enough  to  re- 
ceive it,  and  called,  in  this  country,  the  apron,  as  seen  in 
Fig.  155,  on  page  95. 

A  difficulty  often  occurs,  in  the  entrance  of  water  into 

*  We  are  informed  by  Dr.  Brewster,  that  Burns's  improvement  has 
not  been  introduced  by  him  into  practice,  owing  to  the  difficulty  of 
filling  the  inner  buckets. — Mechanics^  vol.  r.  p.  49 


88  MOVING  FORCES   USED  IN  THE  ARTS. 

the  buckets,  by  the  resistance  of  the  air,  ah'eady  in  the 
bucket,  which  causes  the  water  to  regurgitate,  and  spill. 
This  evil  may  be  entirely  prevented,  by  making  the  spout 
considerably  narrower  than  the  wheel,  so  as  to  leave 
room  for  the  escape  of  the  air,  at  the  two  ends  of  the 
bucket. 

The  pressure  of  the  atmosphere  occasions,  sometimes, 
a  serious  obstruction  to  the  motion  of  overshot-wheels, 
by  causing  a  quantity  of  back-water  to  be  hfted,  or  sucked 
up,  by  the  ascending  inverted  bucket,  when  it  first  leaves 
the  water.  This  difficulty  is  remedied,  by  making  a  few- 
small  holes,  near  the  base  of  the  bucket,  and  communi- 
cating with  the  next  bucket.  Through  these,  the  air  will 
enter,  and  prevent  the  suction.  It  is  true,  that,  when  on 
the  descending  side,  these  holes  will  allow  the  escape  of 
some  w^ater  ;  but,  as  this  water  only  flows  from  one  buck- 
et to  the  next,  its  effect  is  inconsiderable,  when  compared 
with  the  advantage  gained.  Air,  as  Professor  Robison 
observes,  will  escape  through  a  hole,  about  thirty  times 
faster  than  water,  under  the  same  pressure. 

With  respect  to  variations  in  the  fall,  the  same  writer 
remarks,  that,  since  the  active  pressure  is  measured  by 
the  pillar  of  water,  reaching  from  the  horizontal  plane, 
where  it  is  delivered  on  the  wheel,  to  the  horizontal  plane, 
where  it  is  spilled  by  the  wheel,  it  is  evident,  that  it  must 
be  proportionate  to  this  pillar  ;  and,  therefore,  we  must 
deliver  it  as  high,  and  retain  it  as  long,  as  possible.  This 
maxim  obliges  us  to  use  a  wheel,  whose  diameter  is  equal 
to  the  whole  fall.  We  shall  not  gain  anything  by  em- 
ploying a  larger  wheel ;  for,  although  we  should  gain  by 
using  only  that  part  of  the  circumference,  where  the 
weight  will  act  more  perpendicularly  to  the  radius,  we 
shall  lose  more,  by  the  necessity  of  discharging  the  water, 
at  a  greater  height  from  the  bottom.* 

Chain  Wheel. — When  there  is  a  very  small  supply  of 

*  JNIechanical  Philosophy,  vol.  ii.  p.  600. 

On  this  subject,  Dr.  Brewster  remarks,  that,  if  we  employ  a  wheel, 
the  diameter  of  which  is  higher  than  the  fall,  we  may  take  advantage 
of  any  casual  rise  of  the  water,  above  its  usual  level,  and,  by  a  partic- 
ular form  of  the  delivering  sluice,  introduce  the  water,  higher  upon  the 
wheel,  and  thu?  actually  increase  the  height  of  the  fall 


CHAIN-WHEEL. 


89 


water,  falling  from  a  very  great  head,  the  double  overshot- 
wheel,  with  a  chain  of  buckets,  is  a  valuable  machine. 
This  wheel  is  represented  in  Fig.   150,  where  two  rag- 
Fig.  150. 


wheels  are  placed,  one  at  top,  and  the  other  at  bottom, 
and  a  series  of  buckets  are  fixed  to  an  endless  chain,  the 
links  of  which  fall  into  notches  in  the  circumference  of 
the  rag-wheels.  The  water,  issuing  from  the  mill  course, 
is  introduced  into  the  buckets,  on  one  side,  at  top.  The 
descent  of  the  loaded  buckets,  on  this  side,  puts  the  rag- 
wheels  in  motion,  and  the  power  is  conveyed  from  the 
shaft  of  the  upper  wheel,  to  turn  any  kind  of  machinery. 
When  the  buckets  reach  the  bottom,  they  allow  the  water 
to  escape  ;  and,  ascending  empty,  on  the  opposite  side, 
they  again  return  to  the  spout,  to  be  filled  as  before.  In 
this  machine,  the  buckets  have,  in  every  part  of  their 
path,  the  same  mechanical  efiect  to  turn  the  wheels,  and 
they  do  not  allow  the  water  to  escape,  till  they  have 
reached  almost  the  lowest  part  of  the  fall. 

This  species  of  wheel  possesses  another  advantage, 
namely,  that,  by  raising  the  lower  wheel,  and  taking  out 
two  or  three  of  the  buckets,  it  may  be  made  to  work, 
when  there  is  such  a  quantity  of  back-water,  as  would, 
otherwise,  prevent  it  from  moving. 

Dr.  Robison  has  described  a  machine,  of  this  kind,  in 
which  plugs,  or  horizontal  float-boards,  are  fixed  to  a  chain. 


90  MOVING  FORCES  USED  IN  THE  ARTS. 

On  the  descending  side,  these  plugs  pass  through  a  tube, 
a  Htile  greater  in  diameter  than  that  of  the  floats  ;  and  the 
water,  acting  upon  these  floats,  as  it  does  in  the  case  of 
a  breast- wheel,  gives  motion  to  the  two  rag-wheels. 

In  regard  to  the  most  advantageous  velocity  to  be  pro- 
duced, with  a  given  quantity  of  water,  in  an  overshot- 
wheel,  various  mathematicians  have  concluded,  that  th^ 
slower  a  wheel  moves,  the  greater  is  its  power  of  perfor 
mance.  But  the  experiments  of  Mr.  Smeaton  lead  to 
the  conclusion,  that,  in  practice,  there  is  a  limit  of  veloc- 
ity, and  that  overshot- wheels  do  most  work,  when  their 
circumference  moves  at  the  rate  of  about  three  feet  in  a 
second. 

Undershot  Wheel. — An  undershot  water-wheel,  is  a 
wheel  furnished  with  a  series  of  plane  surfaces,  called 
floats,  or  float-boards,  projecting  from  its  circumference, 
for  the  purpose  of  receiving  the  impulse  of  the  water, 
which  is  delivered  by  a  proper  canal,  with  great  velocity, 
upon  the  under  part  of  the  wheel.  A  wheel  of  this  kind 
is  represented  in  Fig.  151. 

Fi2.  151. 


When  an  undershot-wheel  is  put  in  motion,  by  a  stream 
of  water  striking  against  one  of  its  float-boards,  in  a  direc- 
tion at  right  angles  with  the  radius,  the  action  of  the  water 
will  diminish,  as  the  velocity  of  the  wheel  increases,  till, 
at  last,  the  momentum  of  the  water,  or  of  the  accelerating 
force,  is  just  equal  to  the  momentum  of  the  resistance,  or 
of  the  retarding  force.  The  motion  of  the  wheel  will 
then  become  uniform. 

By  calculation,  it  appears  that  a  machine,  thus  driven 


UNDERSHOT-WHEEL.  91 

oy  the  impulse  of  a  stream,  produces  the  greatest  effect, 
or  does  most  work  in  a  given  time,  when  the  wheel  moves 
with  one  third  of  the  velocity  with  which  the  water  moves.* 
But,  in  practice,  this  rule  is  liable  to  some  variation  ;  for 
the  water  does  not  escape,  as  soon  as  it  has  given  its  im- 
pulse, but  is  confined  by  the  channel,  for  some  time,  and 
acts  with  a  variety  of  influences.  In  Mr.  Smeaton's  ex- 
periments, which  are  cited  as  authorities  by  most  writers, 
since  his  time,  it  was  found,  that  an  undershot- wheel, 
when  working  to  the  greatest  advantage,  had  a  velocity, 
which  varied  from  one  third  to  one  half  the  velocity  of 
the  stream  ;  and  that,  in  great  machines,  it  was  nearer  to 
the  latter  of  these  limits,  than  the  former. 

It  is  advantageous,  that  the  size  of  undershot-wheels 
should  be  as  great  as  circumstances  will  permit,  and  it 
ought  never,  says  Dr.  Brewster,  to  be  less  than  seven 
times  the  natural  depth  of  the  stream,  at  the  bottom  of 
the  course. f  In  regard  to  the  best  number  of  float-boards, 
a  difference  of  opinion  has  prevailed  ;  but  it  is  now  gen- 
erally admitted,  that  the  more  float-boards  a  wheel  has, 
the  greater  and  more  uniform  will  be  its  effect.^  Ac- 
cording to  the  experiments  of  Bossut,  it  appeared,  that 
a  wheel  with  forty-eight  float-boards  produced  a  greater 
effect,  than  one  with  twenty-four  ;  and  the  latter,  a  greater 
effect,  than  one  with  twelve.  Smeaton's  experiments 
justify  the  same  conclusion,  though  he  found,  that,  on 
adapting  to  the  wheel  a  circular  sweep  of  such  length, 
that  one  float-board  entered  into  the  curve,  before  anoth- 
er left  it,  the  effect  came  so  near  to  the  former,  as  not  to 
give  any  hopes  of  advancing  it,  by  increasing  the  num- 
ber of  floats,  beyond  twenty-four,  in  the  wheel  experi- 
mented on.§ 

In  regard  to  the  position  of  the  float  boards,  they 
should  not  be  in  the  direction  of  the  radius,  but  inchned 
from  it  slightly,  backwards.     From  the  experiments  of 

*  Playfair's  Outlines  of  Natural  Philosophy,  rol.  i.  p.  214  ;  and  Ro 
bison,  622. 

t  Ferguson's  Mechanics,  vol.  ii.  p.  17. 
t  Gregory's  Mechanics,  vol.  i.  p.  462. 
§  Ibid.  p.  476. 


92       MOVING  FORCES  USED  IN  THE  ARTS. 

Deparcieux  and  Bossut,  it  appears,  that  there  is  a  very 
sensible  advantage  gained,  by  inclining  the  float-boards  to 
the  radius  of  the  wheel,  about  twenty  degrees,  so  that 
the  lowest  float-board  shall  not  be  perpendicular,  but  have 
its  point  turned  up  the  stream,  about  twenty  degrees. 
This  inchnation  causes  the  water  to  heap  up  along  the 
float-board,  and  act  by  its  weight.*  The  floats  should, 
for  this  pui'pose,  be  made  much  broader,  in  the  direction 
of  the  radius,  than  the  vein  of  water,  which  they  inter- 
sect, is  deep.  Another  advantage,  attending  this  obli- 
quity of  the  floats,  is,  that  they  are  less  resisted,  when 
they  rise  out  of  the  water. 

The  best  way  of  delivering  the  water,  on  an  undershot- 
wheel,  in  a  close  mill-course,  according  to  Dr.  Robison, 
is  to  let  it  shde  down  a  very  smooth  channel,  without 
touching  the  wheel,  till  it  arrives  near  the  bottom,  at 
which  place  the  wheel  should  be  exactly  fitted  to  the 
course.  The  floats  should  be  broader  than  the  depth 
of  the  water,  so  as  never  to  be  wholly  immersed,  but  al- 
lowing the  intercepted  water  to  heap  up  against  them. 
If  the  bottom  of  the  course  be  an  arc  of  a  circle,  hav- 
ing a  greater  radius  than  that  of  the  wheel,  the  water, 
which  sHdes  down,  will  be  gradually  intercepted  by  the 
floats,  or  strike  upon  more  than  one  at  a  time.  In  this 
country,  it  is  often  the  practice,  to  admit  the  water,  direct- 
ly, from  the  bottom  of  a  pond,  or  reservoir,  instead  of 
causing  it  to  glide  down  a  separate  channel,  from  near  the 
top  ;  and  this  method  is  found  very  effectual. 

Back  Water. — The  back-w^ater,  or  tail-water,  is  that 
portion  which  has  passed  by  the  wheel.  This  portion  is 
not  only  useless,  but,  in  most  cases,  injurious  ;  since,  by 
its  inertia  and  weight,  it  resists  the  escape  of  the  floats 
and  empty  buckets,  in  their  passage  upward.  Its  effect 
is  increased,  in  times  of  floods,  or  freshets,  so  that  it  is 
often  necessary  to  place  wheels  higher  than  they  other- 
wise would  be,  to  provide  against  it.  A  method  of  get- 
ting rid  of  back-water,  in  times  of  flood,  has  been  invent- 
ed by  Mr.  Perkins,  in  this  country,  and  Mr.  Burns    m 

*  Robison's  Mechanical  Philosophy,  vol.  ii.  p.  625. 


BESANT'S   WHEEL. 


93 


Scotland.     It  consists  in  a  separate  passage,  by  which  a 
current  of  water  is  taken  from  the  mill-lead,  or  flume, 

Fig.  152. 


as  at  A,  in  Fig.  152,  and  passes,  with  great  rapidity, 
under  the  wheel,  and  thence  under  the  flooring,  at  B. 
This  rapid  current  has  the  effect  to  take  ofi',  and  carry 
away,  the  back-water  from  beneath  the  wheel,  while  it  is 
prevented  from  returning,  by  the  force  of  the  same  cur- 
rent, and  the  barrier,  at  C.  The  water,  which  is  expend- 
ed to  maintain  this  current,  is  no  more  than  would  run 
over  the  waste  gate,  in  a  time  of  freshet. 

BesanVs  Wheel. — To  diminish  the  retardation  occa- 
sioned by  back-water,  Mr.  Besant  has  invented  a  wheel, 
in  which  the  floats  are  placed  obhquely  in  a  double  row, 
as  in  Fig.  153,  where  the  wheel  is  represented  as  seen 


edgewise. 


Each  pair  of  floats  foims  an  acute  angle, 
open  at  its  vertex.  By  this  construction,  the  floats  es- 
cape more  gradually,  and  with  less  resistance,  from  the 
back-water,  and  likewise  the  resistance  of  the  atmosphere 


94 


MOVING  FORCES  USED  IN  THE  ARTS. 


is  prevented,  by  the  admission  of  air,  at  the  open  angle 
of  the  floats. 

LambtrVs  Wheel. — As  water  acts  most  advantageously 
upon  undershot-wheels,  when  the  floats  are  perpendicular 
to  the  surfaces  of  the  stream,  it  has  been  attempted,  in 
difllsrent  ways,  to  keep  them  always  in  a  vertical  posi- 
tion. In  the  method  proposed  by  Mr.  Lambert,  the  floats 
are  hung  upon  hinges,  or  pivots,  at  the  extremities  of  th? 
spokes,  and  are  kept  in  a  vertical  position  by  a  large  iro- 
ring,  which  is  suspended  from  the  lower  extremities  of 
the  whole,  and  is  allowed  to  pass,  during  the  revolution, 
through  a  slit  in  the  middle  of  each  float.     In  Fig.  154, 


is  a  view  of  one  side  of  the  wheel,  with  the  ring  attached. 
A,  is  the  centre  of  the  wheel ;  BD,  are  spokes,  or  arms, 
of  the  water-wheel ;  CD,  are  the  float-boards,  which 
are  here  seen  edgewise.  EE,  is  a  large  iron  ring,  con- 
nected by  joints  to  the  lower  extremity  of  all  the  float- 
boards,  and  serving,  by  its  weight,  to  keep  them  in  a  ver- 
tical position.  This  wheel  is,  probably,  too  complicated 
for  common  use.  The  iron  ring  is  kept  from  moving  side- 
ways by  guides,  or  friction-wheels,  placed  at  each  side. 
Breast  Wheel. — The  breast-wheel  is  intermediate  be- 
tween the  overshot,  and  undershot,  wheels,  having  the 
water  delivered  upon  it,  at  about  half  its  height,  or  at  the 


HORIZONTAL  WHEEL. 


95 


level  of  its  axis.  In  breast  wheels,  in  England,  buckets 
are  not  commonly  employed,  but  the  float-boards  are 
fitted  accurately,  with  as  little  play  as  possible,  to  the 
mill  course,  so  that  the  water,  after  acting  upon  the  float- 
boards,  by  its  impulse,  is  detained  between  them  in  the 
mill  course,  and  acts,  by  its  w^eight,  till  it  reaches  the  low- 
est part  of  the  wheel.  A  breast-wheel  is  represented  in 
Fig.  155,  as  it  is  often  constructed  in  this  country,  with 
buckets,  instead  of  floats,  and  with  a  part  of  its  circum- 
ference fitted  to  the  mill  course,  or  apron. 

Fig.  155. 


Horizontal  Wheel. — A  horizontal  wheel,  with  obhque 
floats,  sometimes  called,  in  this  country,  a  tub-wheel,  is 
turned  by  a  current  of  water,  discharged  against  the  floats, 
in  the  manner  represented  in  Fig.  156.     This  method  is 

Fig.  156. 


said  to  be  in  common  use  on  the  continent  of  Europe, 
and  but  seldom  employed  in  England.  It  is  a  disadvan- 
tageous  mode   of  applying;  power,   and  is  only  recom 


96 


MOVING  FORCES  USED  IN  THE  ARTS. 


mended  in  corn-mills,  by  its  simplicity ;  the  millstones  be- 
ing turned  directly  by  the  axis  of  the  water-wheel,  with- 
out the  intervention  of  other  wheels,  or  gearing.  In  the 
same  manner,  another  kind  of  tub-wheel^  which  is  a  sort 
of  inverted  cone,  furnished  with  spiral  floats  on  its  inside, 
is  made  to  revolve  horizontally,  by  discharging  into  it  a 
current  of  water,  from  above. 

Barker^s  Mill, — This  machine,  which  is  also  some- 
times called  Parent'^s  mill,  is  driven  by  an  apphcation  of 
the  force  of  water,  different  from  any  of  those  which  have 
been  already  described.  This  apphcation  consists,  not 
in  the  direct  use  of  the  weight,  or  impulse  of  water,  but 
in  that  of  its  reaction,  or  counter  pressure.  The  princi- 
ple of  this  simple  machine  may  be  seen,  by  inspecting 
Fig.  157,  where  CD,  is  a  revolving,  vertical  tube,  carry- 
ing a  millstone,  [m,]  on  the  upper  part  of  its  axis.  At  th^ 
bottom  of  this  tube,  is  a  horizontal  tube,  AB,  at  the  ex- 
tremities of  which,  are  two  apertures,  A  and  B,  opening 
in  opposite  directions.  A  stream  of  water  is  introduced 
from  the  mill  course  above,  and  flows  out  at  the  apertures, 
at  A  and  B,  and,  in  this  way,  keeps  up  a  continued  hori- 
zontal rotary  motion,  around  the  axis,  [Dm.] 

Fig.  157. 


In  order  to  understand  how  this  rotary  motion  is  pro- 
duced, we  may  suppose  the  apertures  to  be  shut,  and  the 


WIND-POWER. VERTICAL  WINDMILL.  97 

tube,  CD,  filled  with  water.  The  area  of  the  apertures, 
A  and  B,  will  then  be  pressed  outward,  by  a  force,  equal 
to  a  column  of  water  whose  height  is  CD,  and  whose  base 
is  equal  to  the  area  of  the  apertures.  Every  part  of  the 
tube,  AB,  sustains  a  similar  pressure  ;  but,  as  these  pres- 
sures are  balanced,  by  equal  and  opposite  pressures,  the 
machine  remains  at  rest.  But,  when  the  aperture,  at  B, 
is  opened,  the  pressure  at  that  place  is  removed,  and, 
therefore,  the  arm  will  be  carried  round,  in  a  direction 
opposite  to  that  of  the  aperture,  by  a  pressui'e  which  is 
due  to  the  height  of  the  column,  and  area  of  the  aperture. 
The  same  thing  happens  with  the  other  arm,  and  the  two 
pressures  carry  round  the  vertical  axis,  in  the  same  di- 
rection. 

An  Improvement  has  been  made  in  Barker's  mill,  by 
dispensing  with  the  tube,  CD,  retaining  only  its  axis  ; 
and  introducing  the  water,  on  the  under  side  of  the  trans- 
verse tube,  at  D.  For  this  purpose,  the  water  is  brought 
down  from  the  reservoir  at  E,  by  a  separate  passage,  and 
introduced,  at  D,  through  a  water-joint,  which  suffers  the 
arras  of  the  tube  to  revolve,  without  much  loss  of  water. 
Such  a  passage  is  represented  by  the  shaded  part,  EFD. 
The  upward  pressure  of  the  water  may  be  made  to  sup- 
port a  great  part  of  the  w^eight  of  the  machine. 

WIND-POWER. 

Currents  of  water,  being  hmited  in  magnitude,  can  be 
confined,  in  their  action,  to  one  side  of  a  wheel.  But  it 
is  not  easy  to  do  the  same,  with  currents  of  wind,  on  ac- 
count of  their  indefinite  magnitude,  and  the  diificulty  of 
screening  one  half  of  the  wheel,  advantageously,  from  their 
action.  It  is,  therefore,  common,  to  employ  vertical  wind- 
mills, having  a  number  of  sails,  placed  obliquely  to  the 
wind,  and  turning  on  a  horizontal  axis  which  is  parallel 
to  the  wind,  or  nearly  so.  The  action  of  the  wind,  in  this 
case,  is  resolved  into  two  forces  ;  and,  since  the  sails  can- 
not obey  the  first,  by  moving  in  the  direction  of  the  wind, 
they  obey  the  second,  and  move  at  right  angles,  with  it. 

Vertical  Windmill. — The  common  windmill  has,  usu- 
ally, four  sails,  and,  sometimes  six  or  eight.  The  power 
II.  9  XII. 


93  MOVJ^'G  FORCES  USED  IN  THE  ARTS. 

of  these  sails,  to  turn  their  axis,  depends,  when  other  thhrgs 
are  equal,  upon  their  degree  of  obliquity  in  regard  to  the 
wind.  The  angle,  which  is  most  effectual  for  giving  mo 
tion  to  the  sails,  from  a  state  of  rest,  is  an  angle  of  thirty- 
five  and  one  third  degrees  with  the  weather,  or  with  the 
plane  in  which  the  sails  revolve.*  But  the  angle,  which 
produces  the  greatest  action  upon  a  sail  at  rest,  is  not  the 
most  effectual,  when  a  sail  is  in  motion.  As  the  motion 
ncreases,  the  action  of  the  wind  diminishes,  and,  in  or- 
der to  preserve  this  action,  the  sails  require  to  be  brought 
nearer  to  the  wind.  And,  since  each  part  of  the  sail,  in 
revolving,  has  a  different  velocity,  those  parts  which  are 
nearest  the  circumference,  being  swiftest,  are  not  acted 
upon  so  powerfully  by  the  wind,  as  those  which  are  nearer 
the  centre  ;  on  which  account,  it  is  useful  to  give  the  sails 
a  shght  spiral  curvature,  so  as  to  make  the  angle  with  the 
w^eather,  at  the  extremity  of  the  sail,  less  than  it  is  at  the 
centre.  When,  however,  the  sails  are  perfectly  plane^ 
it  is  advantageous,  according  to  Mr.  Smeaton,  that  the 
angle  of  the  sails  with  the  weather  should  be  eighteen 
degrees,  or  less  ;  in  other  words,  that  their  angle  with  the 
axis  should  be  seventy-two  degrees,  or  more.  The  ve- 
locity of  the  sails,  in  this  case,  at  their  outer  extremity, 
is  often  found  to  be  more  than  twice  that  of  the  wind. 

Adjustment  of  Sails. — On  account  of  the  inconstant 
nature  of  the  motion  of  the  wind,  it  is  necessary  to  have 
some  provision,  for  accommodating  the  resistance  of  tlie 
sails,  to  the  degree  of  violence  with  which  the  wind 
blows.  This  is  commonly  done,  by  clothing  and  unclo- 
thing the  sails  ;  that  is,  by  covering,  with  canvass,  or  thin 
boards,  a  greater  or  smaller  portion  of  the  frame  of  the 
sails,  according  to  the  force  of  the  wind,  at  different 
times.  A  method  has  been  devised,  for  producing  the 
same  effect,  by  altering  the  obhquity  of  the  sails  ;  and 
windmills  have  been  so  made,  as  to  regulate  their  own 
adjustment,  by  the  force  of  the  wind.  If  we  suppose  a 
wmdmill,  or  wind-wheel,  to  consist  of  four  arms,  and  that 
the  sails  were  connected  to  these  arms,  at  one  edge,  by 

*  Determined  by  Parent.  See  Brewster's  Ferguson's  Mechanics, 
vol.  ii.  p.  69. 


ADJUSTMENT   OF   SAILS.  99 

means  of  springs,  the  yielding  of  these  springs  would  al- 
low the  sails  to  turn  back,  when  the  wind  should  blow 
with  violence  ;  and  their  elasticity  would  bring  thera  up 
to  the  wind,  whenever  its  force  abated.  This  effect  has 
been  produced  by  a  weight,  acting  on  the  sails,  through  a 
series  of  levers.  A  loose  iron  rod,  passing  through  the 
centre  of  the  axle  of  the  wind-wheel,  receives  the  action 
of  the  weight,  at  one  end,  and  communicates  it  to  the  sails, 
at  the  other.  ' 

Sometimes,  a  governor,  like  that  described  on  page 
77,  is  used,  to  regulate  the  velocity  of  windmills,  which 
are  built  for  grinding,  by  increasing  the  supply  of  corn  to 
be  ground,  or  of  work  to  be  done,  whenever  the  force 
of  the  wind  increases.  The  governor  is  also  applied, 
in  a  very  ingenious  manner,  to  furl  or  unfurl  a  portion  of 
the  sails,  thus  accommodating  them  to  variations  of  the 
wind. 

As  it  is  necessary  that  a  windmill  should  face  the  wind, 
from  vhatever  point  it  blows,  the  whole  machine,  or  a 
part  oi  it,  must  be  capable  of  turning  horizontally.  Some- 
times, the  whole  mill  is  made  to  turn  upon  a  strong  verti- 
cal post,  and  is,  therefore,  called  a  post-mill ;  but,  more 
commonly,  the  roof,-or  head,  only,  revolves,  carrying  with 
it  the  wind-wheel  and  its  shaft,  the  weight  being  supported 
on  friction  rollers.  In  order  that  the  wind  itself  may 
regulate  the  position  of  the  mill,  a  large  vane,  or  weather- 
cock, is  placed  on  the  side  which  is  opposite  the  sails, 
thus  turning  them  always  to  the  wind.  But,  in  large  mills, 
the  motion  is  regulated  by  a  small  supplementary  wind- 
wheel,  or  pair  of  sails,  occupying  the  place  of  the  vane, 
and  situated  at  right  angles  with  the  principal  wind-wheel. 
When  the  windmill  is  in  its  proper  position,  with  its  shaft 
parallel  to  the  wind,  the  supplementary  sails  do  not  turn. 
But,  when  the  wind  changes,  they  are  immediately  brought 
into  action,  and,  by  turning  a  series  of  wheel-work,  they 
gradually  bring  round  the  head,  to  its  proper 'position. 

As  the  resistance,  occasioned  by  the  side  of  the  build- 
ing, makes  a  difference  in  the  force  of  the  wind  upon  the 
upper  and  under  sails,  it  is  common  to  incline  the  sails, 
sind  their  axis,  in  such  a  manner,  that  the  lower  sails  shall 


100  MOVING  FORCES   USED  IN  THE  ARTS. 

be  further  from  the  building,  than  they  would  be,  if  in  a 
vertical  position. 

Horizontal  Windmill. — This  name  is  given  to  those 
windmills  which  turn  on  a  vertical  axis.  Various  meth- 
ods are  employed  in  their  construction,  in  most  of  which, 
the  wind  acts  by  its  direct  impulse,  as  in  an  undershot 
water-wheel.  In  the  most  common  forms,  the  sails,  like 
float-boards,  present  their  broadside  to  the  wind,  on  the 
acting  side  of  the  wheel,  but  are  folded  up,  or  turned 
edgewise,  on  the  returning  side.  These  wheels,  however, 
are  found  to  be  greatly  inferior  to  the  vertical  windmill, 
in  the  amount  of  work  w4iich  they  are  capable  of  perform- 
ing, and,  at  the  present  day,  they  are  little  used. 

As  w^ind  is  the  most  uncertain  of  all  the  moving  agents, 
and  fails,  totally,  in  times  of  calm,  it  is  not  common  to 
depend  upon  this  power,  in  large  works,  provided  other 
moving  forces  can  be  obtained.  The  steam-engine  has, 
in  many  cases,  superseded  it  ;  but  it  is  still  used,  in  cer- 
tain places,  for  grinding  corn,  pum.ping  water,  and  driving 
inferior  machinery.  Upon  the  ocean,  it  is  a  locomotive 
agent,  of  incalculable  importance. 

"^  STEAM-POWER. 

Steam. — The  power  of  steam  depends  on  the  tendency 
which  water  possesses,  to  expand  into  vapor,  when  heated 
to  a  certain  temperature.  Many  other  substances,  and, 
perhaps,  all,  have  the  same  tendency  ;  and  those  which 
are  volatile,  at  low  temperatures,  might,  doubtless,  be 
made  the  sources  of  moving  power,  in  the  arts.  But, 
since  water,  which  is  the  most  cheap  and  abundant  of 
these  substances,  fortunately  possesses,  also,  the  greatest 
number  of  requisites  for  an  expansive  agent,  it  is  not  like- 
ly to  be  superseded  by  any  other  material. 

When  water  is  converted  into  steam,  it  expands  to 
about  one  thousand  seven  hundred  times  its  original  vol- 
ume,* so  that  a  cubic  inch  of  water  furnishes  about  a 
cubic  foot  of  steam,  at  two  hundred  and  twelve  degrees 

*  One  thousand  six  hundred  and  thirty-three  times,  according  to 
Gay-Lussac.  See  Ure's  Dictionary,  article  Caloric.  One  thousand 
seven  hundred  and  eleven  times,  according  to  Tredgold. 


STEAM-POWER.  101 

of  Fahrenheit,  under  the  common  pressure  of  the  atmos- 
phere. Water  cannot,  however,  be  converted  immedi- 
ately into  steam,  by  the  application  of  a  boiling  tempeia- 
ture,  but  requires  a  certain  period,  to  effect  its  volatiliza- 
tion. This  period  is  about  six  times  as  great,  as  that 
which  is  necessary  to  raise  it  from  the  freezing  to  the 
boiling  point,  supposing  the  supply  of  heat  to  be  uniform. 
The  amount  of  heat,  which  is  absorbed,  or  rendered 
latent,  by  the  conversion  of  water  into  steam,  is  about 
nine  hundred  and  fifty  degrees.* 

The  power  of  steam,  to  produce  motion  in  other  bodies, 
depends  upon  the  increase  of  its  own  volume  ;  and  what- 
ever body  resists  this  increase,  will  be  acted  upon  by  a 
force,  proportionate  to  the  elastic  powe**  of  the  steam,  and 
the  circumstances  under  which  the  resistance  is  made. 
In  a  vessel  boiling  in  the  open  air,  we  are  not  sensible  of 
the  magnitude  of  this  force,  because  the  steam,  and  the 
resisting  medium,  against  which  it  acts,  are  both  invisible. 
But,  when  we  consider  that  the  steam,  when  first  gener- 
ated, has  to  lift  off  from  the  water,  before  it  can  assume 
its  elastic  form,  the  weight  of  the  superincumbent  atmos- 
phere, and  that  this  weight,  in  the  atmospheric  column 
which  presses  on  a  vessel,  only  two  feet  in  diameter,  is 
equal  to  several  tons,  we  may  easily  conceive  of  the  force 
which  attends  this  expansion. 

Furthermore,  since  steam  has  the  property  of  imme- 
diately condensing  into  water,  as  soon  as  its  temperature 
is  reduced  below  two  hundred  and  twelve  degrees,  it  fol- 
lows, that  the  atmospheric  weight  which  has  been  lifted, 
by  the  formation  of  the  steam,  will  immediately  fall,  when 
the  steam  condenses  ;  and  with  a  force,  equal  to  that  by 
which  it  was  raised.  This  furnishes  an  indirect,  or  sec- 
ondary, application  of  the  power  of  steam. 

But  the  powers  of  steam  are  not  Hmited  by  the  effects 
which  it  produces,  at  the  common  boihng  temperature. 
If  steam  be  separated  from  the  contact  of  water,  and 
exposed  to  a  further  increase  of  temperature,  it  will  con- 
tinue to  expand,  by  the  law  which  governs  the  increase 

*  Nine  hundred  and  fifty,  according  to  Watt.  Nine  hundred  an^ 
sixty-seven,  Ure. 

9* 


f02      MOVING  FORCES  USED  IN  THE  ARTS. 

of  all  gaseous  bodies,  and  will  double  its  volume,  once, 
for  every  four  hundred  and  eighty  degrees  of  Fahrenheit's 
thermometer.*  And,  furthermore,  if  water  itself  be  en- 
closed in  strong  vessels,  and  thus  heated,  its  expansive 
force  will  be  prodigiously  greater  than  that  of  steam  alone  ; 
since  every  particle  of  the  water  tends  to  generate  steam, 
of  high  temperature,  and  to  occupy  the  space  which  is 
due  to  such  steam.  In  a  common  boiler,  containing  wa- 
ter and  steam,  each  addition  of  caloric  causes  a  fresh 
portion  of  steam  to  rise,  and  to  add  its  elastic  force  to 
that  of  the  steam  previously  existing,  so  that  an  excessive 
pressure  is  soon  exerted  against  the  inside  of  the  vessel, 
if  the  augmentation  of  heat  has  been  considerable.  At 
two  hundred  and  twelve  degrees,  Fahrenheit,  steam  has 
an  elastic  force,  equal  to  the  pressure  of  the  atmosphere. 
If  it  be  farther  heated,  in  contact  with  water,  it  will  have 
a  force,  equal  to  that  of  two  atmospheres,  at  about  two 
hundred  and  fifty  degrees  ;  of  four  atmospheres,  at  two 
hundred  and  ninety-three  degrees  ;  and  of  eight  atmos- 
pheres, at  three  hundred  and  forty-four  degrees.  These 
are  the  results,  in  round  numbers,  of  Mr.  Southern's 
experiments  ;  and  they  are  nearly  confirmed,  by  those  of 
Drs.  Robison  and  Ure.f 

At  temperatures  below  two  hundred  and  twelve  de- 
grees, steam  has  still  a  certain  elastic  force,  which  dis- 
covers itself,  whenever  the  pressure  of  the  atmosphere  is 
taken  off.  Thus,  its  elastic  force,  at  one  hundred  and 
eighty  degrees,  is  equal  to  about  half  an  atmosphere  ;  and 
it  has  some  force,  at  all  temperatures  above  the  freezing 
point. 

Steam  expands  in  all  directions,  alike,  and  is  useful,  as 
a  moving  agent,  only  by  its  pressure.  It  cannot,  like  water 
and  wind,  be  made  to  act  advantageously  by  its  impulse, 

*  Ure's  Dictionary  of  Chemistry,  Art.  Caloric  and  Gas. 

1  The  recent  and  elaborate  experiments  of  Messr?.  Arago  and  Du- 
Icng,  have  corrected  these  results,  and  carried  the  scale  as  high  as  fifty 
atmospheres.  Thus,  an  elastic  force,  equal  to  the  pressure  of  twenty 
atmospheres,  is  produced  by  a  heat  of  about  four  hundred  and  eighteen 
degrees,  Fahrenheit,  and  one  of  fifty  atmospheres,  by  five  hundred  and 
ten  degrees. 


APPLICATIONS   OF  STEAM.  103 

m  the  open  air  ;  for  the  momentum  of  so  hght  a  fluid,  un- 
less generated  in  vast  quantities,  would  be  inconsiderable. 
Some  of  the  earliest  attempts,  however,  at  forming  a 
steam-engine,  consisted  in  directing  the  current  of  steam, 
from  the  mouth  of  an  eolipile,  against  the  vanes,  or  floats, 
cf  a  revolving  wheel.*  In  order  that  the  pressure  of 
steam  may  be  rendered  available,  in  machinery,  the  steam 
must  be  confined  within  a  cavity,  which  is  air-tight,  and 
so  constructed,  that  its  dimensions,  or  capacity,  may  be 
altered,  without  altering  its  tightness.  When  the  steam 
enters  such  a  vessel,  it  enlarges  the  actual  cavity,  by  caus- 
ing some  movable  part  to  recede  before  it,  and,  from  this 
movable  part,  motion  is  communicated  to  machinery.  A 
hollow  cylinder,  having  a  movable  piston,  accurately  fitted 
to  its  bore,  constitutes  a  vessel  of  this  kind.  It  was  used, 
more  than  a  century  ago,  by  Newcomen  ;  and,  as  it  is 
found  to  combine  more  advantages,  than  any  other  kind 
of  arrangement,  for  motion,  its  use  has  never  been  super- 
seded The  piston,  thus  employed,  has  a  reciprocating 
motion,  which  is  converted,  when  necessary,  into  a  rotary 
one,  by  the  appropriate  mechanism. 

Applications  of  Steam, — The  pressure  of  steam  is 
capable  of  being  applied  to  use,  in  three  different  ways  ; 
and  these  modes  have  given  rise  to  some  of  the  most  im- 
portant varieties  of  the  steam-engine.  The  three  methods 
which  are  used,  for  obtaining  power  from  steam,  are,  1. 
By  condensation,  as  in  the  atmospheric  engine.  2.  By 
generation,  as  in  the  simple  high-pressure  engines.  3. 
By  expansion,  as  in  Woolf's  engine.  Watt's  expansion 
engine,  and  some  others.  These  methods  have  been  il- 
lustrated, by  Mr.  Tredgold,  by  a  figure  like  that  on  page 
104.  Suppose  a  cylindric  vessel,  ABCD,  to  be  plac- 
ed in  a  vertical  position,  with  a  given  depth  of  water  in 
the  bottom,  and  an  air-tight  piston,  above  the  water,  bal- 
anced by  a  weight,  D,  equal  to  its  own  vveight  and  fric- 
tion. In  this  state,  let  heat  be  applied  to  the  base,  AC  ; 
then,  as  the  water  becomes  converted  into  steam,  of  slight- 
ly greater  force  than  the  atmospheric  pressure,  the  piston 

*  Such  was  the  engine  of  Branca,  in  the  beginning  of  the  seven- 
feenth  century. 


104 


MOVING  FORCES   USED  IN  THE  ARTS, 
Fig.  158. 

\0 


will  rise,  till  the  whole  water  is  in  a  state  of  steam.  It 
must  be  observed,  however,  that  the  generation  of  this 
steam,  which  is  of  atmospheric  elastic  force,  affords  no 
available  power,  but  is  simply  sufficient  to  balance  the 
column  of  atmospheric  air,  and  exclude  it  from  a  given 
height  of  the  cylinder. 

By  Condensation. — In  the  state  of  things  just  describ- 
ed, if  the  steam  be  suddenly  condensed  into  water,  by  the 
application  of  cold,  it  is  obvious,  that  the  piston  will  be 
driven  downward,  with  a  force,  equal  to  the  weight  of  the 
atmosphere  which  presses  on  the  piston,  and  through  a 
distance,  equal  to  that  which  the  piston  had  been  raised, 
by  the  generation  of  steam.  It  follows,  that  the  power 
of  steam,  which  is  of  atmos^^heric  elastic  force,  is,  when 
speedily  condensed,  directly  proportionate  to  the  space 
which  it  occupies.  If  the  temperature  of  this  steam  be 
raised  above  two  hundred  and  twelve  degrees,  it  will  oc- 


gener'ation  of  steam.  lOd 

cupy  a  larger  space,  the  increase  being  equal  to  the  ex- 
pansion of  steam,  by  the  given  change  of  temperature. 
But  a  quantity  of  heat,  nearly  equivalent  to  the  increase 
of  volume,  will  be  absorbed  ;  and  hence,  says  Mr.  Tred- 
gold,  the  effect  of  a  given  quantity  of  fuel  would  not  be 
Increased  by  the  expedient.* 

By  Generation, — Suppose  the  same  cylinder  and  ap 
paratus  to  have  heat  applied  to  its  base,  with  only  the 
difference  of  the  piston  being  loaded  with  a  given  pres- 
sure per  inch  of  its  area.  The  generation  of  the  steam 
will  raise  the  loaded  piston  ;  but  the  height,  through  which 
it  will  be  raised,  will  be  less  than  if  it  were  not  loaded. 
The  steam  having  to  act  in  opposition,  both  to  the  pres- 
sure of  the  atmosphere,  and  the  load^Dn  the  piston,  the 
space  it  will  occupy  will  be  in  the  inverse  ratio  of  the 
pressures  which  oppose  it,  supposing  the  steam  of  atmos- 
pheric elastic  force  to  have  been  of  the  same  temperature. 
Thus,  if  the  load  on  the  piston  be  equal  to  twice  the  at- 
mospheric pressure,  the  piston  will  be  raised  only  one 
third  of  the  height ;  but,  on  rapid  condensation,  it  de- 
scends with  three  times  the  pressure  ;  and,  therefore, 
whether  the  steam  be  generated  of  atmospheric  elastic 
force,  or  of  a  greater  force,  the  power  it  affords,  by  gen- 
eration and  condensation,  is  the  same,  at  the  same  tem- 
perature, and  this  power  is  directly  as  the  elastic  force 
of  the  steam,  multiplied  by  the  space  it  occupies,  sup- 
posing that  the  motion  of  the  piston  is  rectilinear. 

But  if,  as  in  the  last  case,  a  loaded  piston  be  raised, 
and  then  a  valve  be  opened,  which  allows  the  steam  to 
escape,  the  whole  power  gained  will  be  equal  only  to  the 
weight  raised,  descending  from  the  height  to  which  it  was 
raised  ;  and  the  power,  which  would  have  resulted  from 
condensation,  will  be  lost,  and  the  loss  is  equal  to  the 
pressure  of  the  atmosphere,  acting  through  the  height,  to 
which  the  piston  w^as  raised  by  steam.  This  is  the  na- 
ture of  the  common  high-pressure  steam-engine.  It  is 
obvious,  that  the  greater  the  elastic  force  of  the  steam, 
the  less  is  the  proportionate  loss,  by  neglecting  to  con- 

*  Tredgold,  on  the  Steam  Engine,  p.  157 — 159. 


106  MOVING  FORCES   USED  IN  THE  ARTS. 

dense  it  under  these  circumstances  ;  but  it  may  be  re- 
marked, that,  unless  the  valve  aperture  be  equal  to  the 
diameter  of  the  cylinder,  the  steam  cannot  escape  at  the 
necessary  rate,  without  part  of  the  load  acting  to  expel 
it ;  and  so  much  more  of  the  effective  force  will,  of 
course,  be  lost.  The  effective  power  is  as  the  space  the 
steam  occupies,  multiplied  by  the  excess  of  elastic  force 
above  the  atmospheric  pressure. 

By  Expansion. — Retaining  the  same  loaded  piston,  let 
it  be  raised,  by  the  conversion  of  a  given  quantity  of  water 
into  steam,  to  the  height  which  corresponds  to  the  load 
and  temperature.  Then,  if  the  load  on  the  piston  be 
wholly  removed,  at  that  height,  the  steam  will  raise  the 
piston,  by  expancflhg,  till  it  becomes  nearly  of  the  same 
elastic  force  as  the  atmosphere,  and  its  condensation  will 
produce  the  same  effect,  as  if  the  steam  had  been  gener- 
ated of  atmospheric  elastic  force,  at  first.  Consequently, 
the  effect,  in  raising  the  load  on  the  piston,  is  wholly  ad- 
ditional, and  the  joint  effect  of  a  high-pressure  and  con- 
densing engine  is  produced,  by  the  same  steam.  Hence, 
by  this  combination  of  effect,  the  power  of  steam,  of  high 
elastic  force,  will  be  nearly  doubled. 

This  is  not,  however,  the  mode  by  which  steam  can 
be  applied  with  the  greatest  advantage  ;  for,  instead  of 
removing  the  load  on  the  piston,  wholly,  at  the  height  to 
which  it  was  raised,  by  the  generation  of  the  high  pres- 
sure steam,  a  part  of  it  may  be  removed,  and  then  the 
steam  would  expand,  to  a  height  depending  on  the  por- 
tion of  the  load  removed  ;  at  that  height,  remove  a  second 
portion,  and  so  on,  successively,  till  the  steam  becomes 
of  atmospheric  elastic  force.  In  this  case,  as  far  as  the 
load  was  raised,  in  parts,  by  the  expansion  of  the  steam, 
the  effect  is  greater  than  in  the  preceding  combination. 
This  illustrates  the  principle  of  the  high-pressure  expan- 
sion engines  of  Evans,  Woolf,  and  some  others. 

Again  :  let  the  piston  be  raised,  unloaded,  as  in  the  first 
case,  by  the  conversion  of  a  certain  quantity  of  water  into 
steam  of  atmospheric  elastic  force.  When  the  piston  is 
at  that  height,  add  a  weight,  equal  to  half  the  atmospheric 
pressure,  to  the  line  passing  over  the  pulley.      Then  the 


STEAM-ENGINE.  107 

elastic  force  of  the  steam  being  unbalanced,  the  piston 
/  would  rise,  till  that  elastic  force  would  be  half  the  atmo- 
spheric pressure,  or  till  the  piston  would  be  at  double  its 
former  height.  Now,  suppose  the  steam  to  be  condensed, 
and  the  weight  removed  from  the  pulley,  at  the  same  in- 
stant. Then,  the  power  of  the  descent,  after  deducting 
the  power  added  to  produce  the  ascent,  will  be  one  half 
iijore  than  it  would  have  been,  by  simply  condensing  steam 
of  atmospheric  elastic  force.  This  illustrates  the  prin- 
ciple of  the  expansion  engines  of  Hornblower  and  Watt ; 
and  it  differs  from  the  principle  of  Woolf,  in  using  steam 
only  of  low  pressure.  The  weight,  added  to  the  line  pas- 
sing over  the  pulley,  is  introduced  here,  merely  to  ex- 
emplify the  mode  of  applying  a  portion  of  the  excess  of 
power,  which  is  accumulated  in  the  fly-wheel,  in  one  part 
of  the  operation,  to  assist  the  machine,  through  the  rest. 

It  has  been  assumed,  that  steam,  at  least  of  atmosphe- 
ric elastic  force,  was  generated  ;  but  thi§  is  not  a  necessary 
condition,  for  it  frequently  occurs,  that  engines  work  with 
steam  of  less  elastic  force.  The  same  mode  of  illustra- 
tion will  show  whence  this  happens.  Let  half  the  pressure 
of  the  atmosphere,  on  the  piston,  be  balanced  by  a  weight 
over  a  pulley.  Then,  on  the  application  of  heat,  steam 
of  half  the  atm.ospheric  elastic  force  would  be  generated, 
and  raise  the  piston  to  double  the  height  that  it  would  be 
raised,  in  common  cases,  by  steam,  capable  of  supporting 
the  atmospheric  pressure.  Consequently,  on  its  being 
condensed,  the  descending  force  will  be  half  the  atmos- 
pheric pressure,  acting  through  double  the  height ;  and 
the  steam  produces  the  same  effect,  as  before. 

The  foregoing  methods  of  the  application  of  steam  will 
be  found  apparent,  in  the  different  forms  of  the  steam-en- 
gine, in  which  they  have  been  called  into  use. 

The  Steam  Engine. — The  steam-engine  is  a  machine, 
by  which  the  power,  derived  from  steam,  is  converted  to 
practical  use.  It  has  occupied  the  attention  of  philoso- 
phers and  artists,  for  more  than  a  century,  and  is  now 
brought  to  so  great  a  degree  of  perfection,  as,  in  the  opin- 
ion of  many  scientific  men,  to  leave  little  probability  of 
tts  further  improvement.      Whether  viewed  with  reference 


108  MOVING  FORCES   USED   IN   THE   ARTS. 

to  the  great  skill  which  has  been  employed,  in  perfecting 
it,  or  the  importance  and  extent  of  its  application,  it  may 
justly  be  viewed  as  the  noblest  production  of  the  arts,  in 
modern  times.  For  acquiring  a  clear  conception  of  the 
steam-engine,  as  it  is  now  commonly  constructed,  it  will 
be  useful  to  consider,  first,  the  boiler^  in  which  the  power 
is  generated,  and,  second,  the  engine,  in  which  it  is  di- 
rected, and  apphed  to  use. 

Boiler. — On  account  of  the  gradual  rate  at  which  wa- 
ter boils  away,  it  is  necessary,  in  most  engines,  to  keep  a 
large  quantity  constantly  heatecj,  to  afford  steam  with 
sufficient  rapidity  for  its  consumption  by  the  engine.  This 
water  is  enclosed  in  a  strong,  tight,  vessel,  called  the 
boiler,  which  is  made  of  iron,  or  copper,  and  rests  in 
contact  with  a  furnace.  It  is  requisite,  that  a  boiler  should 
be  of  sufficient  strength,  to  resist  the  greatest  pressure 
which  is  ever  liable  to  occur,  from  the  expansion  of  the 
steam.  It  must  also  offer  a  sufficient  extent  of  surface 
to  the  fire,  to  insure  the  requisite  amount  of  vaporization. 
In  common  low-pressure  boilers,  it  requires  about  eight 
feet  of  surface  of  the  boiler  to  be  exposed  to  the  action 
of  the  fire  and  flame,  to  boil  off  a  cubic  foot  of  water,  in 
an  hour  ;  and  a  cubic  foot  of  water,  thus  converted  into 
steam,  is  equal  to  a  one-horse  power.* 

The  strongest  form  for  a  boiler,  and  one  of  the  earliest 
which  was  used,  is  that  of  a  sphere  ;  but  this  form  is  the 
one  which  offers  least  surface  to  the  fire.  The  figure  of 
a  cylinder  is,  on  many  accounts,  the  best ;  and  it  is  now 
extensively  used,  especially  for  engines  of  high  pressure 
It  has  the  advantage  of  being  easily  constructed  from 
sheets  of  metal,  and  the  form  is  of  equal  strength,  except 
at  the  ends.  In  such  a  boiler,  the  ends  should  be  made 
thicker  than  the  other  parts.  The  furnace  is  so  con- 
structed, that  the  flame  and  hot  smoke  may  pass  undei 
the  whole  length  of  the  boiler,  and  afterwards  around  both 
its  sides,  before  escaping  to  the  chimney. 

In  what  are  caWed  flue-boilers,  a  cylindrical  furnace  is 
placed  within  a  cylindrical  boiler,  so  that  the  fuel  is  sur- 

*  See  Tredgold,  on  the  Stean-.  Engire,  with  the  following  correction, 
p.  124,  Ime  2,  from  the  bottom      For  steam,  read  water 


EOILER. 


109 


rounded  by  water,  on  all  sides,  and  communicates  to  it 
nearly  all  its  heat,  except  the  portion  which  passes  up  the 
chimney. 

In  large  engines,  which  are  of  low  pressure,  the  form 
of  the  boiler,  which  was  used  by  Mr.  Watt,  still  contin- 
ues to  be  employed,  particularly  in  England.  In  this 
boiler,  the  upper  half  is  a  semi-cyhnder,  while  the  lowei 
half  is  nearly  rectangular,  with  the  under  side  concave,  so 
that  a  cross  section  would  nearly  resemble  a  horse-shoe. 
This  boiler  is  less  strong  than  those  of  a  cvhndrical  form, 
but  it  offers  a  larger  surface  to  the  fire,  without  occupy- 
mg  much  more  space.  A  boiler  of  th'":  kmd,  as  it  is  fit- 
ted up  in  large  engines,  with  append? Z'^:^  for  regulating  its 
Fig.  159. 


Ml 


no  MOVING   FORCES    USED   IN  THE   ARTS. 

own  fire,  water,  and  steam,  is  represented  in  the  figure, 
[159,]  on  the  preceding  page.  A  part  of  the  furnace  is 
supposed  to  be  taken  away,  to  bring  the  boiler  into  view ; 
and,  also,  a  portion  of  the  boiler  is  removed,  to  show  its 
inside. 

Jlppendagcs. — In  the  figure  above  referred  to,  BBBB, 
is  the  boiler,  made  of  thick  sheets,  or  plates,  of  rolled 
iron,  strongly  riveted  together,  a  part  of  which  are  remov- 
ed, to  show  the  interior.  It  is  supposed  to  be  half  full  of 
water,  at  the  boiling  temperature.  C,  is  the  steam-gauge^ 
the  object  of  which  is  to  determine  the  degree  of  pressure 
acting  within  the  boiler.  It  is  a  bent  iron  tube,  or  invert- 
ed syphon,  one  end  of  which  communicates  with  the  boil- 
er, and  the  other  end  with  the  atmosphere.  The  tube  js 
partly  filled  with  mercury,  and,  as  the  pressure  of  the 
steam  increases,  the  mercury  will  be  driven  outward,  and 
will  rise  in  the  external  leg  of  the  syphon.  As  the  height 
of  the  column  of  mercury  cannot  be  seen,  the  tube  being 
opaque,  a  small  wooden  stem  is  made  to  float  in  the  tube, 
with  its  end  projecting  by  the  side  of  a  graduated  scale. 
Every  inch  in  height,  which  the  stem  rises,  shows  a  dif- 
ference of  two  inches  in  the  two  surfaces  of  the  mercury 
in  the  tube,  and  indicates  a  pressure  of  about  a  pound, 
upon  every  square  inch  of  the  inner  surface  of  the  boiler. 
And,  as  low-pressure  engines  are  seldom  worked  with 
more  than  three  or  four  pounds  to  the  square  inch,  the 
mercury  seldom  rises  higher  than  three  or  four  inches,  in 
such  engines.  In  high-pressure  engines,  the  mercurial 
gauge  is  not  so  easily  applied  ;  for  these  engines  are  fre- 
quently worked,  at  a  pressure  of  several  atmospheres,  and 
each  additional  atmosphere  requires  an  addition,  of  nearly 
fifteen  inches,  to  the  column  of  mercury. 

W,  is  a  large  opening,  called  the  man-hole^  of  sufficient 
size  to  permit  a  man  to  enter  the  boiler,  to  clean  or  exam- 
ine it.  It  is  closed  by  a  strong  iron  plate.  D,  is  the 
steam-pipe,  which  conveys  the  steam  to  the  engine.  It 
is  provided  with  a  throttle-valve,  which  is  a  circular  disc, 
or  partition,  turning  on  an  axis,  and  connected  with  the 
governor,  described  on  page  77.  Its  use  is  to  regulate 
the  supply  of  steam,  by  closing  the  pipe,  i    the  engine 


STEAM-ENGINE  APPENDAGES.  ^        111 

goes  too  fast,  or  by  opening  it,  if  it  is  too  slow.  FF, 
are  the  gauge-cocks^  which  indicate  the  height  of  water 
in  the  boiler.  Their  extremities  stand  at  different  depths, 
in  the  boiler,  one  being  below  the  surface  of  the  water, 
and  the  other  above  it.  When  the  water  is  at  the  proper 
height,  one  of  these  will  emit  steam,  on  being  opened, 
and  the  oiher  will  emit  water.  They  are  frequently  plac- 
ed on  the  end,  instead  of  the  top,  of  the  boiler. 

For  keeping  up  a  regular  supply  of  water  to  the  boiler, 
a  vertical  tube,  6,  called  the  feed-pipe,  is  used.  Upon 
Its  top,  is  a  small  cistern,  HHHH,  which  is  kept  full  of 
water,  by  a  pump,  worked  by  the  engine.  At  the  bottom 
of  this  cistern,  is  a  valve,  E,  connected  to  one  end  of  the 
lever,  [a6.]  At  the  other  end  of  this  lever,  is  a  wire,  [f/c,] 
which  passes  through  a  steam-tight  opening,  at  [c?,]  and 
supports  a  stone  float,  [c,]  upon  the  surface  of  the  water, 
the  stone  being  counterbalanced  by  a  weight,  at  the  valve, 
[e.]  When  the  w^ater  lowers,  in  the  boile*'  -he  stone  float 
descends,  and,  by  acting  upon  the  lever,  [u-u  J  opens  the 
<^alve,  [e.]  Water  immediately  flows  in,  from  the  cistern, 
and  continues  to  do  so,  till  the  float  rises,  and  shuts  the 
valve.  It  will  be  observed,  that  the  column  of  water,  in 
the  feed-pipe,  must  be  sufficiently  high  to  counterbalance 
the  pressure  of  steam,  in  the  boiler.  On  this  account, 
it  can  not  be  applied  in  high-pressure  engines,  without 
making  it  of  a  very  inconvenient  height.  In  these  en- 
gines, therefore,  water  is  supplied  to  the  boiler,  by  a 
small  forcing  pump,  worked  by  one  of  the  reciprocating 
parts  of  the  engine  ;  and  it  is  frequently  heated,  before 
being  pumped  in,  that  it  may  not  check  the  production  of 
steam. 

For  the  purpose  of  regulating  the  fire,  the  feed-pipe 
is  furnished  with  an  iron  bucket,  O,  hung  by  a  chain, 
which  passes  over  two  pullies,  PP,  and  is  attached  by  its 
other  extremity  to  an  iron  damper.  A,  which  commands 
the  chimney.  When  the  steam  in  the  boiler  is  urged  to 
too  great  an  extent,  it  forces  the  water  upward,  in  the 
feed-pipe,  and  causes  the  iron  bucket  to  ascend.  This 
lowers  the  damper  into  the  smoke-flue,  and,  by  thus 
intercepting  the  current  of  air,  checks  the  force  of  the 


112  MOVING  FORCES   USED   IN   THE  ARTS. 

fire.     In  some  boilers,  the  passage,  which  brings  air  to 
the  fire,  is  intercepted,  instead  of  the  smoke-flue. 

To  prevent  the  boiler  from  bursting,  if,  by  accident, 
the  pressure  of  the  steam  should  become  too  great  for  the 
strength  of  the  boiler,  a  safety-valve  is  provided,  at  S, 
opening  outward.  It  is  kept  down  by  a  weight,  so  that 
it  cannot  be  raised,"  except  by  a  greater  force  than  that 
which  is  required  to  work  the  engine.  It  is  highly  im- 
portant, however,  that  it  should  not  be  liable  to  any  other 
weight,  or  encumbrance,  than  that  which  the  engine  re- 
quires ;  and,  to  prevent  this  danger,  it  is  enclosed  in  a 
case,  which  is  kept  locked.  When  the  engine  stops 
working,  or  the  steam  is  generated  too  rapidly  for  its  ex- 
penditure, the  safety-valve  rises,  and  the  superfluous  steam 
rushes  out,  with  a  hissing  noise. 

Another  safety-valve  is  also  provided,  which  differs 
from  the  preceding,  in  opening  inwards.  It  is  kept  up 
by  a  counter  weight,  on  a  lever,  and  its  use  is  to  prevent 
the  weight  of  the  atmosphere  from  crushing  in  the  sides 
of  the  boiler,  when  the  engine  stops  w^orking,  and  the 
steam  cools. 

As  boilers  are  usually  proved,  before  being  submitted 
to  use,  the  accident  of  bursting  does  not  happen,  from  a 
general  want  of  strength,  unless  the  safety-valve  be  over- 
loaded. It  is  most  likely  to  happen,  either  from  neglect, 
in  suffering  the  water  to  get  too  low,  in  some  part  of  the 
boiler,  so  that  the  metal  is  excessively  heated,  or  else, 
from  the  corrosion  of  the  metal,  in  places,  by  oxidation, 
after  long  exposure  to  the  fire.  If  a  sediment  is  suffered 
to  accumulate,  to  a  considerable  depth,  on  the  bottom  of 
the  boiler,  it  has  the  effect  to  exclude  the  water  from  con- 
tact with  the  metal,  so  that  the  metal  becomes  hotter,  and 
is  more  rapidly  oxidated,  and  even  softened,  by  the  heat 

The  violent  explosions  which  have  sometimes  occur 
red,  projecting  the  contents  and  fragments  of  the  boiler 
to  a  great  distance,  have  been  rationally  accounted  for, 
by  supposing  that  certain  parts  of  the  metal,  through  neg- 
lect, become  heated  to  a  high  temperature,  and,  that  por- 
tions of  water,  being  suddenly  brought  into  contiguity  with 
them,  produce  steam,  of  which  the  initial  elastic  force  is 


STEAM-ENGINE  APPENDAGES.  113 

extremely  great.  In  this  case,  the  boiler  may  burst,  be- 
fore the  inertia  of  the  water-  or  safety-valves,  is  over- 
come ;  and  the  stronger  is  the  boiler,  the  greater  may  be 
the  explosion. 

As  a  great  number  of  lives  have  been  lost  by  the  ex- 
plosion of  boilers,  particularly  on  board  of  steam-boats, 
much  attention  has  been  bestowed  on  the  means  of  pre- 
venting such  accidents.  The  principal  attempts  have 
consisted,  in  a  more  accurate  regulation  of  the  safety- 
valves,  and  in  the  introduction  of  plugs  of  fusible  metal, 
which  melt,  when  the  temperature  is  raised  a  little  above 
the  boihng  point  of  water,  and  thus  suffer  the  steam  to 
escape.  But  absolute  security  has  only  been  found,  in 
placing  the  boiler  in  such  a  situation,  that,  if  it  should 
burst,  it  would  occasion  no  injury  to  the  passengers  in 
the  boat.  This  is  effected,  by  placing  the  engine  in  a 
boat  by  itself,  or  by  interposing  a  strong  barrier  between 
the  boilers,  and  the  persons  on  board  the  boat.  Mr. 
Tread  well  has  proposed  to  use  the  steam,  at  a  pressure 
not  greater  than  that  of  the  atmosphere,  and  to  compen- 
sate the  loss  of  force,  by  an  increase  in  the  size  of  the 
cylinder  and  piston. 

Besides  the  forms  of  the  boiler,  already  mentioned, 
various  others  have  been  employed,  such  as  combinations 
of  tubes,  and  other  figures,  intended  to  multiply  surface, 
for  the  purpose  of  raising  more  steam,  from  the  same 
amount  of  water,  in  a  given  time.  They  have  been 
applied  in  some  high-pressure  engines,  but,  in  most  ca- 
ses, the  simpler  forms  are  preferred.*  In  Brathwaite  and 
Ericsson's  engine,  which  has  been  apphed,  with  partic- 
ular success,  to  propelling  carriages  on  rail-roads,  the  hot 
air  of  the  furnace  is  forcibly  drawn,  in  a  circuitous  flue, 
through  the  boiler,  by  means  of  a  revolving,  fan-like  ap- 
paratus ;  thus  communicating  to  the  boiler  a  greater  quan- 
tity of  heat,  in  a  given  time,  than  could  be  obtained  from 
the  common  atmospheric  draught. 

*  In  Perkins's  engine,  a  strong  vessel,  called  a  generator ^  is  kept  full 
of  water  heated  to  a  high  temperature.     Portion?  of  the  water  are  suc- 
cessively forced  out  ;  and  reliance  is  placed  on  the  heat  already  in  this 
water,  to  produce  from  it  the  requisite  amount  of  steam. 
10* 


114      MOVING  FORCES  USED  IN  THE  ARTS. 

Engine. — The  steam  being  generated  in  sufficient 
quantities  in  the  boiler,  it  is  next  applied  to  use  in  the 
working,  or  moving,  part,  which  we  have  called  the  en- 
gine. Of  this  engine,  a  great  variety  of  forms  and  mod- 
ifications have  been  proposed,  and  adopted,  at  different 
times.  A  few  of  those,  which  are  effectual  in  their  prin- 
ciple, and  most  extensively  employed,  will  now  be  con- 
sidered. 

j^on- condensing  Engine. — The  simplest  form  of  the 
steam-engine  is  that  of  the  non-condensing,  commonly 
called  the  high-pressure,  engine.  In  this  engine,  the  ap- 
paratus for  condensation  is  dispensed  with,  and  the  steam 
is  worked  at  a  high  temperature,  and  afterwards  discharg- 
ed into  the  open  air.  Of  course,  a  part  of  the  force  of 
the  steam  is  expended,  in  overcoming  the  pressure  of  the 
atmosphere,  and  the  surplus,  only,  can  be  applied  to  drive 
machinery.  That  this  surplus  may  be  sufficient  to  pro- 
duce the  requisite  power,  a  pressure  of  thirty  or  forty 
pounds,  on  a  circular  inch,  above  the  atmospheric  pres- 
sure, is  commonly  kept  up  in  these  engines.* 

The  manner,  in  which  the  engine  is  made  to  operate, 
fs,  briefly,  as  follows.  The  steam,  in  escaping  from  the 
boiler  to  the  open  air,  is  obliged  to  pass  through  the  cyl- 
inder, the  cavity  of  which  is  closed,  except  where  it  com- 
municates with  the  valves.  By  the  opening  and  shut- 
ting of  these  valves,  the  steam  is  made  to  enter  the  cylin- 
der, alternately,  at  each  end,  and  escape  by  the  opposite 
end.  But,  in  doing  this,  its  passage  is  always  intercepted 
by  the  piston  ;  so  that,  before  it  can  escape,  it  must  move 
the  piston  from  one  end  to  the  other  of  the  cylinder. 
The  repetition  of  this  movement  gives  motion  to  a  beam, 
or  other  alternating  part,  from  which  it  is  communicated, 
by  a  connecting  rod  and  crank,  to  a  fly-wdieel,  in  the  same 
manner  as  is  seen  in  the  condensing  engine,  [PI.  III.] 
hereafter  to  be  described.  The  figure,  there  represented, 
may  be  considered  as  a  non-condensing  engine,  if  we  re- 
move from  it  the  condenser,  and  its  appendages,  occupy- 
ing the  lower  part  of  the  plate.  B,  represents  the  boiler  ; 
^^,  the  pipe,  which  conveys  the  steam  ;  D,  the  cylinder  ; 

*  See  Tredgold,  on  the  Steam  Engine,  p.  181. 


CONDENSING  ENGINES.  115 

E,  the  piston;  F,  the  beam;  [A,]  the  crank;  G,  the 
fly-wheel. 

The  different  apparatus  of  valves,  by  which  the  entrance 
and  escape  of  steam  is  regulated  ;  also,  the  other  appen- 
dages of  the  engine,  will  be  considered  in  another  place. 
In  arranging  the  time  of  their  opening  and  shutting,  it  is 
usual  to  allow  not  quite  all  the  steam  to  escape,  at  the 
end  of  the  stroke.  A  small  portion  is  retained,  to  receive 
the  shock  of  the  piston,  and,  by  its  elasticity,  to  destroy 
its  momentum,  and  cause  it  to  recoil  back,  without  loss 
of  force. 

Non-condensing  engines  sometimes  work  by  the  gener- 
ative force  of  steam,  and,  sometimes,  by  the  generative  and 
expansive  force.  They  are  used  in  cases  where  simphc- 
ity  and  lightness  are  required,  as  in  locomotive  engines  ; 
also,  in  situations  where  a  sufficient  supply  of  water,  for 
condensation,  cannot  easily  be  obtained.  They  are  infe- 
rior, in  safety,  to  condensing  engines  ;  yet,  as  they  cost 
much  less  at  the  outset,  for  the  expense  of  building,  they 
are  often  preferred  for  small,  or  temporary,  works.  In 
proportion  to  the  high  temperature  at  which  the  steam 
is  worked,  great  caution  is  necessary,  in  regard  to  the 
strength  and  management  of  the  boiler,  in  these  engines. 

Condensing  Engines. — Engines  of  this  class  are  fitted 
up,  with  an  apparatus  for  condensing  the  steam  into  water, 
so  that  a  vacuum,  nearly  complete,  is  formed  in  one  part 
of  the  cylinder,  just  before  the  stroke  of  the  piston,  into 
that  part,  takes  place.  By  this  construction,  the  resist- 
ance of  the  atmosphere  is  avoided  ;  and,  thus,  the  power 
of  the  engine,  to  perform  work,  is  much  increased.  The 
steam,  also,  is  sufficiently  powerful  for  use,  at  compara- 
tively low  temperatures  ;  and  hence  arises  the  increase  of 
safety  which  is  found  in  Imc-pressure  engines,  a  name  giv- 
en to  those  condensing  engines,  which  are  worked  with 
steam  of  moderate  elastic  force. 

In  the  atmospheric  engine^  invented  by  Newcomen,  the 
piston  was  raised  by  the  steam,  aided  by  a  counter  weight, 
till  it  arrived  at  the  top  of  the  cylinder,  which  was  left 
perfectly  open.  A  jet  of  v/ater  was  then  admitted  into 
rhe  bottom  of  the  cylinder,  which  suddenly  condensed 


116  MOVING  FORCES   USED  IN  THE  ARTS. 

tlie  steam,  so  that,  a  vacuum  being  formed,  the  piston  was 
driven  down,  by  a  force  equal  to  tlie  weight  of  the  column 
of  superincumbent  air.  The  water  was  now  excluded  by 
a  stop-cock,  and  the  steam  readmitted.  The  piston  was 
thus  again  raised,  and  the  process  repeated  as  before. 

A  great  inconvenience  attended  this  method,  arising 
from  the  circumstance,  that  the  cylinder  itself  required  to 
be  heated  and  cooled,  at  each  stroke  of  t.ie  piston,  thus  oc- 
casioning great  delay,  and  an  mmecessary  expense,  both 
of  fuel,  and  of  cold  water.  To  remedy  this  evil,  Mr. 
Watt  invented  the  separate  condenser^  which  is  a  strong 
vessel,  situated  at  a  distance  from  the  cylinder,  but  com- 
municating with  it  by  a  pipe,  so  as  to  form  with  it  a  com- 
mon cavity,  without  reducing,  materially,  its  temperature. 
Into  this  vessel,  the  jet  of  cold  water  is  thrown,  and,  as 
all  the  communicating  pipes  are  governed  by  valves,  or 
cocks,  the  cyhnder,  below  the  piston,  is  alternately  filled 
with  steam,  from  the  boiler,  and  emptied  of  steam,  by  the 
condenser. 

In  the  double-acting  engine,  invented  by  Mr.  Watt, 
the  top  of  the  cylinder  was  closed,  and  rendered  air-tight, 
the  rod  of  the  piston,  only,  passing  through  it.  Thus, 
the  cylinder  is  divided,  by  the  piston,  into  two  cavities, 
both  communicating  with  the  boiler,  and  both  with  the 
condenser.  By  the  aid  of  valves,  an  alternate  communi- 
cation is  kept  up,  so  that  the  steam,  being  alternately  ad- 
mitted at  both  ends,  impels  the  piston,  successively,  in 
both  directions,  while  the  condenser,  at  the  same  time, 
destroys  the  resistance.  In  this  engine,  compared  with 
the  single  engine  of  Mr.  Watt,  which  was  previously  in 
use,  a  double  quantity  of  steam  is  used,  and  a  doubk 
power  exerted,  in  the  same  space  and  time. 

Description. — In  PL  III.,  's  a  view  of  a  double-acting 
steam-engine,  nearly  as  constructed  by  Murray,  and  upon 
the  same  general  principles  as  those  of  Mr.  Watt,  vary- 
ing, however,  in  the  valves,  and  some  other  particulars. 

A,  represents  the  furnace,  which  is  here  shown  in  sec- 
tion, as  is  also  the  boiler,  above  it,  and  all  the  principa\ 
cavities  of  the  engine.  The  flame  and  hot  smoke,  after 
passing  underneath  the  boiler,  for  its  whole  length,  return 


DOUBLE-ACTING   STEAM-ENGINE.  117 

through  the  side  passages,  [c/c/,]  before  they  are  dischar- 
ged into  the  chimney. 

B,  is  the  boiler,  which,  in  this  example,  is  of  a  cyhn- 
drical  form,  a  shape  better  adapted  for  strength,  than  that 
I'epresented  in  Fig.  159.  The  appendages  represented  in 
Fig.  159  arenot  here  repeated.  Some  of  them,  indeed, 
are  not  used  in  steam-boats,  and  in  small  engines.  The 
boiler  is  commonly  made  of  sheets  of  iron,  strongly  rivet- 
ed together,  and  tightened  by  hammering.  If  intended  to 
contain  salt  water,  the  boiler  is  made  of  copper,  to  prevent 
corrosion. 

CCC,  is  the  steam-pipe,  which  carries  the  steam  from 
the  boiler  to  the  cylinder,  through  the  valve,  I.  It  is  made 
of  cast-iron,  and  its  joints  screwed  together  by  flanges. 

D,  is  the  cylinder,  communicating,  by  passages  at  the 
top  and  bottom,  with  the  valve,  I.  The  cylinder  is  made 
of  cast-iron,  and  accurately  bored,  to  make  its  inner  sur- 
face smooth  and  true. 

E,  is  the  piston,  which,  by  its  rod,  [e,]  gives  an  alter- 
nating motion  to  the  beam,  [//,]  about  its  centre,  F,  the 
other  end  of  which,  by  another  connecting  rod,  [^,]  gives 
motion  to  the  heavy  fly-wheel,  GG,  by  means  of  a  crank, 
[/i.]  Thus,  after  the  engine  has  begun  to  work,  its  power 
is  accumulated  in  the  .fly-wheel,  and  a  circular  motion 
may  be  communicated  from  it  to  any  machinery. 

H,  is  an  eccentric  circle,  on  the  axle  of  the  fly-wheel, 
G.  It  gives  motion  through  the  medium  of  its  levers, 
[z6M' and  yz^']  and  the  connecting  rods,  [Jiicxy,  and;2:I,]  in 
a  manner  easily  understood,  by  inspection,  to  the  valve,  I. 

I,  is  a  coffer-valve,  capable  of  sliding  up  and  down, 
and  having  a  cavity  on  the  side  next  the  cylinder.  By 
moving  up  and  down,  it  opens  and  shuts  the  passages,  ana 
admits  the  steam,  alternately,  to  each  end  of  the  cylinder  ; 
and,  at  the  same  time,  forms  a  communication  between 
the  opposite  end,  and  the  condenser. 

W,  is  the  governor,  which  regulates  the  speed  of  the 
engine.  It  resembles  the  governor  described  in  chap.  XV. 
but  has  its  movable  collar  on  the  top,  at  [5.]  It  may  be 
turned  by  a  band,  from  the  axle  of  the  fly-wheel,  or  placed 
directly  over  the  axle,  and  geared  to  it  by  bevel-w^heels. 


118  MOVING  FORCES  USED  IN  THE   ARTS. 

When  the  fly-wheel  moves  too  fast,  the  balls  of  the  gov- 
ernor recede  from  their  centre,  and,  by  acting  on  a  lever, 
[rs,']  cause  it  to  turn  upon  its  fulcrum,  [i,]  and  partially  to 
close  the  steam-pipe,  by  a  throttle-valve,  at  K.  When 
the  velocity  abates,  the  balls  subside,  and  the  valve  opens, 
so  as  to  admit  more  steam. 

L,  is  the  air-pump,  the  use  of  which  is,  to  discharge 
the  air  and  water,  which  collect  in  the  condenser,  M. 

M,  is  the  condenser,  which  is  an  empty,  cylindrical 
vessel,  immersed  in  a  cistern  of  cold  water,  SS,  and 
communicating  with  the  cylinder  by  the  pipe,  O.  It  has 
a  valve,  or  cock,  communicating  with  the  cistern,  and 
moved  by  the  rod,  [gg-,']  through  which  a  jet  of  cold 
water  enters  it,  for  the  purpose  of  condensing  the  steam. 

N,  is  a  small  cistern,  filled  with  water.  Into  this  cis- 
tern enters  a  pipe,  from  the  condenser  M,  the  top  of 
vvdiich  pipe  is  covered  by  a  valve,  which  is  called  the 
bloio-valve^  or,  sometimes,  the  snifting-valve.  Through 
this  valve,  the  air,  contained  in  the  cylinder,  D,  and 
passages  from  it,  is  discharged,  on  the  engine  being  first 
set  in  motion. 

O,  is  the  eduction-pipe,  which  conducts  the  steam  from 
the  valve,  I,  to  the  condenser,  M. 

P,  is  the  pump,  which  supplies  w:ith  water  the  cistern,  or 
cold  well,  SS,  in  which  the  condenser  and  discharging 
pump  stand. 

QQ,  are  iron  columns,  which  support  the  beam.  Of 
these,  the  engine  has  four,  although  only  two  are  shown 
They  stand  upon  one  entire  plate,  seen  edgewise,  on 
which  the  principal  parts  of  the  engine  are  fixed. 

PtR,  is  the  recess  below  the  floor,  for  containing  the 
cistern  of  the  discharging  pump,  condenser,  &c. 

The  condenser,  M,  and  the  air  pump,  L,  communicate 
by  means  of  a  horizontal  pipe,  containing  a  valve,  [m,] 
opening  towards  the  pump  ;  the  piston  [n,]  of  this  pump, 
also  contains  two  valves,  and  the  cistern,  T,  at  the  top 
of  the  pump-cylinder,  contains  other  two  valves,  which, 
like  those  of  the  piston,  [n,]  open  upwards.  When  the 
piston,  E,  of  the  cylinder,  is  depressed,  the  piston  [n,]  of 
the  discharging  pump,  it  will  be  obvious  to  inspection, 


EXPANSION  ENGINES.  119 

will  be  depressed,  likewise,  and  its  valves  open,  while  the 
valve,  [?7i,]  closes  ;  hence,  the  water  of  the  condensed 
steam,  as  well  as  the  injection  water,  and  any  vapor  of 
air,  which  may  be  present,  having  passed  through  the 
valve,  [m,]  passes  through  the  piston,  [n  ;]  and,  when  that 
piston  is  drawn  up,  its  valves  close,  and  prevent  their 
return,  as  in  common  pump-w'ork.  The  water  and  air, 
that  have  thus  got  above  the  piston,  as  the  latter  rises, 
open  the  valves  at  the  bottom  of  the  cistern,  T,  in  which 
the  water  remains  till  it  is  full ;  but  the  air  passes  into  the 
atmosphere.  As  the  water  in  the  cistern,  T,  is  in  a  hot 
state,  a  part  of  it,  for  the  purpose  of  economizing  fuel,  is 
pumped  up,  and  returned  to  the  boiler,  the  pump-rod 
being  attached  to  the  great  beam. 

The  steam,  constantly  rushing  into  the  condenser,  M, 
has  a  perpetual  tendency  to  heat  that  vessel,  as  well  as 
the  water  of  the  cistern,  SS,  in  which  it  stands  ;  the 
whole  of  the  steam,  if  this  were  unchecked,  would  not  be 
condensed,  or  the  condensation  would  not  be  sufficiently 
rapid,  because  the  injection  water  itself  flows  out  of  this 
cistern.  A  part  of  the  water  is,  therefore,  allowed  to 
flow  from  this  cistern  by  a  waste  pipe,  and  an  equal  quan- 
tity of  cold  water  is  constantly  supphed  by  the  pump,  P. 

The  cylinder,  D,  is,  in  many  cases,  surrounded  by  a 
case,  to  keep  it  from  being  cooled  too  much,  by  contact 
with  the  external  atmosphere. 

Expansion  Engines. — The  steam,  which  impels  an 
engine  is  always  diminished  in  volume,  by  the  resistance 
which  it  has  to  overcome,  and  tends,  naturally,  to  occupy 
a  larger  space,  than  that  to  which  it  is  confined,  while  the 
engine  is  at  work.  If  it  be  dismissed  into  the  air,  or  into 
the  condenser,  while  under  its  greatest  working  pressure, 
it  will  not  have  produced  all  the  useful  effect,  which  it  is 
capable  of  afibrding.  If,  on  the  contrary,  it  be  separa- 
ted, and  placed  under  circumstances,  where  it  can  still 
expand  further,  before  it  is  dismissed,  this  expansion  will 
be  so  much  additional  gain  to  the  power  of  the  engine. 
Its  general  principles  have  already  been  discussed. 

The  expansive  power  of  steam  may  be  converted  to 
use,  in  various  ways,  and  most  of  the  common  forms  of 


120         movi:jg  forces  used  in  the  arts. 

the  steam-engine  rnav  be  made  to  act  expansively,  by  a 
proper  arrangement  of  their  valves.  In  Watt's  engine, 
this  effect  is  produced,  by  cutting  off  the  steam  from  the 
cylinder,  before  the  stroke  of  the  piston  is  completed, 
leaving  it  to  the  steam,  already  in  the  cylinder,  to  assist, 
by  its  expansion,  in  completmg  the  stroke.  The  steam 
in  the  boiler,  being  thus  intercepted,  acts  only  at  intervals 
Nevertheless,  its  whole  disposable  force  is  accumulated  in 
the  fly-wheel,  while,  at  the  same  time,  the  force,  arising 
from  the  expansion  of  steam  in  the  cylinder,  serves  to  in- 
crease the  total  amount.  A  great  augmentation  is  thus 
produced,  in  the  useful  effect  of  an  engine,  with  the  same 
amount  of  fuel  and  water. 

Mr.  Hornblower,  who  was  one  of  the  first  inventors 
of  the  apphcation  of  expansive  steam,  employed  two 
cylinders,  having  their  pistons  connected  to  the  same 
beam.  In  the  smaller  of  these,  the  steam  was  used,  at 
full  pressure,  after  which  it  was  discharged  into  the  lar- 
ger cylinder,  where  it  again  acted,  by  its  expansive  force. 
This  method  affords  a  more  equable  mode  of  applying 
the  expansive  force  of  steam,  than  that  used  by  Mr 
Watt ;  but  the  engine  is  more  complex  and  expensive. 

Mr.  Woolf  afterwards  adopted  the  plan  of  two  cyhn 
ders,  with  the  addition  of  using  his  steam  at  a  high  pres- 
sure, together  with  a  condenser.  He  appears  to  have 
exaggerated  the  expansive  force  of  steam,  at  high  tem- 
peratures, as  various  other  projectors  have  done.  His 
engines,  however,  continue  to  be  used  and  approved,  in 
different  parts  of  England  and  Wales,  and  their  perfor- 
mance is  stated  to  exceed  that  of  any  other  kinds. 

Condenser. — It  has  already  been  stated,  that,  in  the 
original  atmospheric  engine  of  Newcomen,  the  steam  was 
condensed  by  a  jet  of  cold  water,  thrown  into  the  cylin- 
der. A  great  improvement,  in  the  economy  of  heat,  was 
made  by  Mr.  Watt,  who  introduced  the  separate  con- 
denser. But,  even  with  uis  improvement,  there  is  some 
loss  of  power,  in  consequence  of  the  necessity  of  con- 
tinually pumping  out  the  water,  which  has  been  injected, 
to  condense  the  steam.  Sea-water,  also,  gives  trouble, 
by  the  deposit  of  salt  in  the  boiler.      To  obviate  these 


VALVES.  121 

difficulties,  condensers  have  been  made,  of  a  multitude  of 
small  tubes,  communicating  with  the  eduction-pipe,  and 
kept  immersed  in  cold  water.  In  this  way,  sufficient 
heat  escapes,  through  the  surface  of  the  tubes,  to  condense 
the  steam,  without  the  necessity  of  injection  ;  and  the 
water  is  kept  fresh.  Some  of  the  Atlantic  steam-boats 
have  had  condensers  of  this  kind.  A  difficulty,  however, 
is  found,  in  the  expansion  and  contraction  of  the  tubes, 
which  makes  it  necessary  to  receive  the  ends  of  all  of 
them  in  stuffing  boxes,  which  admit  motion,  but  are  li- 
able to  get  out  of  order.  In  a  large  engine,  now  work- 
ing at  the  Iron-works,  in  Boston,  Mr.  Treadwell  has  in- 
troduced a  condenser,  the  tubes  of  which  are  bows,  having 
both  ends  soldered  to  the  same  surface,  and,  therefore, 
not  liable  to  be  displaced,  by  expansion,  or  contraction. 
Valves. — The  valves  of  steam-engines  are  shutters, 
which  guard  the  avenues  to  the  boiler  and  condenser,  so 
that,  by  opening  and  shutting  them,  at  the  required  time, 
the  steam  may  be  made  to  enter,  or  escape,  at  either  end 
of  the  cylinder.  Valves,  of  a  great  variety  of  forms, 
have  been  used  in  different  engines,  some  of  which  have 
a  reciprocating,  others,  a  rotary,  motion.  The  puppet 
valve  is  a  cone,  or  frustum  of  a  cone,  which  is  fitted,  like 
a  cover,  to  a  conical  aperture,  which  it  opens,  by  rising, 
and  closes,  by  faUing.  Sliding  valves  are  those  which  do 
not  rise,  but  slide  on  and  off  of  their  apertures.  Som.e 
of  these  have  a  cavity,  on  their  under  side,  capable  of 
connecting  two  apertures  together,  or  of  forming  a  com- 
munication between  them,  while  a  third  aperture  is  shi;t. 
Rotary  valves  are  usually  constructed  like  common  stop- 
cocks, excepting  that  they  comme'nd  more  passages  than 
one,  at  the  same  time.  If  the  handle  be  placed  in  one 
position,  it  opens  one  pfssage,  while  it  closes  another  ;  if 
in  a  different  position,  it  closes  the  first,  and  opens  the 
second.  A  throttle  valve  is  a  partition,  turning  on  an 
axis,  and  placed  across  the  interior  of  a  pipe.  If  turned 
edgewise,  it  permits  the  steam  to  pass  ;  but,  if  turned 
transversely,  it  obstructs  its  passage.  This  valve  is  com- 
monly placed  in  the  main  steam-pipe,  and  connected  with 

II.  11  XII. 


122  MOVIXG  FORCES  USED  IN  THE  ARTS. 

the  governor,  to  regulate  the  quantity  of  steam  supplied 
by  the  boiler. 

On  account  of  the  heat  which  is  kept  up  in  steam-en- 
gines, the  principal  valves  require  to  be  of  metal,  and  are 
fitted,  by  grinding,  closely  to  their  seats.  Valves  made 
with  leather,  like  the  common  clack  valve  of  a  pump, 
can  only  be  used  about  the  condenser,  where  the  temper- 
ature is  low. 

Pistons. — As  the  piston  is  hable  to  continual  wear,  by 
"ts  friction  against  the  inside  of  the  cylinder,  it  can  only 
be  kept  sufficiently  tight,  by  rendering  its  circumference 
elastic.  This  is  commonly  done,  by  winding  it  with 
hemp,  loosely  twisted.  The  hemp  packing,  however, 
gets  out  of  order,  in  time,  and  requires  to  be  renewed. 
To  remedy  this  evil,  various  plans  have  been  introduced, 
for  making  elastic  pistons  of  metal  only.  The  pistons 
invented  by  Cartwright  and  Barton,  consist  of  several 
parallel  circular  plates,  in  close  contact  with  each  other. 
These  are  cut  into  segments,  and  the  segments  pressed 
outward,  by  steel  springs,  care  being  taken,  that  the  fis- 
sures, in  the  different  plates,  do  not  coincide.  In  the  pis- 
ton of  Jessop,  a  spiral  coil  of  steel  is  wound  on  the  cir- 
cumference of  the  piston,  which  expands,  by  its  own  elas- 
ticity, so  as  to  keep  in  tight  contact  with  the  cylinder. 
To  increase  the  tightness  and  elasticity  of  the  piston,  a 
hempen  packing  is  placed  within  the  coil. 

Parallel  Motion. — A  simple  form  of  a  parallel  mo- 
tion, for  converting  the  rectilinear  motion  of  the  piston 
into  the  curvilinear  one  of  the  beam,  has  already  been 
described,  on  page  66.  Another  form  is  shown  in  Plate 
III.,  w^here  the  rod,  [«^,]  turns  upon  the  joint,  [«,]  as  a 
fixed  centre,  while  the  rod,  [c6,]  turns  upon  [6,]  as  a  cen- 
tre. While  the  point,  [c,]  would  describe  a  curve  about 
ts  centre,  [6,]  the  point,  [6,]  describes  an  opposite  curve 
about  its  centre,  [a.]  These  two  curvatures  compensate 
each  other,  so  that  the  point,  [c,]  to  which  the  piston  is 
attached,  describes  nearly  a  straight  line. 

The  parallel  motion  was  introduced  by  Mr.  Watt,  and 
is,  probably,  attended  with  less  friction  than  any  other  ar- 
rangement, for  effecting  the  same  object.     It  requires 


LOCOMOTIVE    ENGINE.  123 

however,  to  be  constracted  with  great  accuracy.  Va- 
rious other  methods  have  been  apphed,  to  convert  the 
rectilinear  into  a  curvihnear  movement.  Sometimes,  the 
piston  is  confined  to  its  path  by  guides,  or  friction  wheels, 
and  connected  to  the  beam  by  a  double  joint.  In  New- 
comen's  engine,  where  the  principal  force  was  in  the 
downward  stroke,  the  piston  was  connected,  by  a  chain, 
to  an  arched  head,  at  the  end  of  the  beam.  In  Cart- 
wright's  engine,  the  piston  was  attached  to  two  opposite 
cranks,  which  were  geared  together,  as  shown  on  page 
66.  In  some  of  Murray's  engines,  the  epicycloidal 
movement  was  employed.  [See  page  69.]*  In  Maud- 
slay's  engine,  and  some  others,  instead  of  a  beam,  a 
cross-head  is  used,  the  whole  of  which  moves  up  and 
down,  in  guides,  instead  of  turning  on  a  centre.  In  the 
vibrating  engines  of  Lester,  and  others,  the  cylinder  is 
hung  upon  a  movable  axis  ;  and,  in  Morey's  engine,  the 
cylinder  revolves,  hke  a  fly-wheel,  the  piston  being  made 
to  act  on  a  fixed  crank. 

Locomotive  Engine. — This  engine  is  used,  as  a  propel- 
ling powder,  on  rail-ways,  and  has  been  introduced  in  a 
previous  chapter.  The  accompanying  figure  shows  the 
internal  construction  of  one  of  these  machines. 

F,  represents  the  fire-box,  or  place  where  the  fire  is 
kept  ;  D,  the  door,  through  which  the  fuel  is  introduced  ; 
G,  one  of  the  bars  of  the  grate,  at  the  bottom  ;  the  spa- 
ces, marked  B,  are  the  interior  of  the  boiler,  in  which  the 
water  stands,  at  the  height  indicated  by  the  dotted  line 
The  boiler  is  closed  on  all  sides ;  all  its  openings  being 
guarded  by  valves.  The  tubes,  marked  [ee,]  conduct 
the  smoke  and  flame  of  the  fuel,  through  the  boiler,  to  the 
chimney,  CC,  serving,  at  the  same  time,  to  communi- 
cate the  heat  to  the  remotest  part  of  the  boiler.  By  this 
arrangement,  none  of  the  heat  is  lost ;  as  these  tubes  are 
all  surrounded  by  the  water.  SSS,  is  the  steam-pipe, 
open  at  the  top,  BS,  having  a  steam-tight  cock,  or  reg- 
ulator, V,  which  is  opened  and  shut  by  the  crank,  H, 

*  For  an  account  and  figure  of  an  engine,  of  this  kind,  see  Farey  on 
the  Steam  Engine,  p.  686,  and  Plate  XVII. 


124  MOVING   FORCES   USED   IN  THE   ARTS. 

extending  outside  of  the  boiler,  and  which  is  managed  by 
the  engineer. 

The  operation  of  the  machine  is  as  follows  :  The  steam 
being  generated  in  great  abundance,  in  the  boiler,  and 
being  unable  to  escape  out  of  it,  acquires  a  considerable 
degree  of  elastic  force.  If,  at  that  moment,  the  cock,  V, 
is  opened,  by  the  handle,  H,  the  steam,  penetrating  into 
the  tube,  S,  at  the  top,  near  X,  and  in  the  direction  of 
the  arrows,  passes  through  the  tube,  and  the  valve,  V, 
and  enters  the  valve-box,  [i.]  There,  a  sliding  valve, 
loo,^  which  moves  at  the  same  time  with  the  machine, 
opens  for  the  steam  a  communication,  successively,  with 
each  end  of  the  cylinder.  Thus,  in  the  figure,  the  en- 
trance, on  the  left  hand  of  the  sliding  valve,  is  represented 
as  being  open,  and  the  steam  follows,  in  the  direction  of 
the  dotted  line,  into  the  cylinder,  where  its  expansive 
force  will  move  the  piston,  P,  in  the  direction  of  the  ar- 
row. The  steam,  or  air,  on  the  other  side  of  the  piston, 
passes  out,  in  the  direction  of  the  dotted  line,  to  [it,]  which 
communicates  with  the  tube,  [tt^]  from  which  it  passes 
into  the  chimney,  C,  and  thence  into  the  open  air.  The 
sliding  valve,  [oo,']  now  moves,  and  leaves  the  right-hand 
aperture  open,  while  it  closes  the  one  on  the  left.  The 
steam  then  draws  the  piston  back;  and  that  portion  of 
steam,  on  the  left  of  the  piston,  having  performed  its  of- 
fice, passes  out  of  the  aperture,  [it,]  an  opening  to  which 
is  made,  by  the  new  position  of  the  sliding  valve.  Thus, 
the  sliding  valve,  opening  a  communication,  alternately, 
with  each  side  of  the  piston,  the  steam  is  admitted  on 
both  sides  of  the  piston,  and,  having  performed  its  office, 
it  passes  through  the  aperture,  [it,]  to  the  tube,  [tt^]  and 
the  chimney,  C,  and  from  thence  into  the  open  air. 

Motion  being  thus  given  to  the  piston,  it  is  communi- 
cated, by  means  of  the  rod,  R,  and  the  beam,  G,  to  the 
crank,  K  ;  which,  being  connected  u-ith  the  axle  of  the 
wheel,  causes  it  to  turn,  and  thus  moves  the  machine. 

Power  of  the  Steam  Engine. — Dr.  Lardner  has  given 
the  following  statements,  relating  to  the  power  of  the 
steam-engine. 

[n  a  report,  published  m  1835,  it  was  announced,  that 


POWER  OF  THE   STEAM-ENGINE.  125 

a  steam-engine,  erected  at  a  copper-mine,  near  St.  Aus 
lie,  in  Cornwall,  bad  raised,  by  its  average  work,  ninety 
five  millions  of  pounds,  one  foot  bigb,  witb  a  busbel  ol 
coals.  Tbis  enormous  mecbanical  effect  baving  given 
rise  to  some  doubts,  as  to  tbe  correctness  of  tbe  experi- 
ments, on  wbicb  tbe  report  was  founded,  it  was  agreed, 
tbat  anotber  trial  sbould  be  made,  in  tbe  presence  of  a 
number  of  competent,  and  disinterested,  witnesses.  Tbis 
trial,  accordingly,  took  place,  and  was  witnessed  by  a 
Dumber  of  the  most  experienced  mining  engineers,  and 
agents.  Tbe  result  was,  tbat,  for  every  busbel  of  coals, 
consumed  under  tbe  boiler,  tbe  engine  raised  one  hun- 
dred and  tw^enty-five  and  a  balf  milbons  of  pounds  weight, 
one  foot  bigb. 

It  may  not  be  uninteresting  to  illustrate  tbe  amount  of 
mecbanical  virtue,  which  is  thus  proved  to  reside  in  coals, 
in  a  more  familiar  manner. 

Since  a  bushel  of  coal  w^eighs  eighty-four  pounds,  and 
can  lift  fifty-six  thousand  and  twenty-seven  tons,  a  foot 
high,  it  follows,  that  a  pound  of  coal  would  raise  six  hun- 
dred and  sixty-seven  tons,  the  same  height  ;  and,  tbat  an 
ounce  of  coal  would  raise  forty-two  tons,  one  foot  high, 
or  it  would  raise  eighteen  pounds,  a  mile  high. 

Since  a  force  of  eighteen  pounds  is  capable  of  drawing 
two  tons,  upon  a  rail- way,  it  follows,  that  an  ounce  of 
coal  possesses  mecbanical  virtue  sufiicient  to  draw^  two 
tons,  a  mile,  or  one  ton,  two  miles,  upon  a  level  rail-way. 

The  circumference  of  tbe  earth  measures  twenty-five 
thousand  miles.  If  it  w^ere  begirt  by  an  iron  rail-way,  a 
load  of  one  ton  would  be  drawn  round  it,  in  six  weeks,  by 
the  amount  of  mecbanical  power  which  resides  in  the 
third  part  of  a  ton  of  coals. 

The  great  pyramid  of  Egypt  stands  upon  a  base,  meas- 
uring seven  hundred  feet,  each  way,  and  is  five  hundred 
feet  bigb  ;  its  weight  being  12,760,000,000  pounds.  To 
construct  it,  cost  tbe  labor  of  one  hundred  thousand  men, 
for  tw^enty  years.  Its  materials  w^ould  be  raised  from  the 
ground,  to  their  present  position,  by  the  combustion  of 
four  hundred  and  seventy-nine  tons  of  coals. 

The  weight  of  metal,  in  tbe  Menai  bridge,  is  four  mil 


i26  MOVING  FORCES   USED  IN  THE  ARTS. 

lion  pounds,  and  its  height,  above  tlie  level  of  the  water, 
is  one  hundred  and  twenty  feet.  Its  mass  might  be  lifted 
from  the  level  of  the  water,  to  its  present  position,  by  the 
combustion  of  four  bushels  of  coals. 

Projected  Improvements. — Besides  the  improvements 
which  have  been  actually  efiected,  in  the  construction 
and  application  of  the  steam-engine,  a  variety  of  projects, 
for  increasing  the  power  and  usefulness  of  this  agent, 
have,  from  time  to  time,  occupied  the  attention  of  ingen- 
ious men.  Of  the  improvements  which  have  been  at- 
tempted, some  are  opposed  by  obstacles,  which  have  not 
yet  been  satisfactorily  surmounted,  and  others,  by  difficul- 
ties, in  themselves,  insurmountable.  The  following  have 
been  among  the  most  prominent  subjects  of  speculation. 

1.  Rotative  Engines. — These  are  engines,  in  which 
the  steam  is  so  applied,  as  to  produce  a  direct  rotary  mo- 
tion, without  the  intervention  of  a  rectilinear  movement. 
Engines,  on  this  principle,  have  been  constructed  in  many 
different  ways.  An  idea  of  one  of  the  most  obvious 
forms,  may  be  obtained  from  the  eccentric  pumps,  de 
scribed  in  the  following  chapter,  which  have  been  con 
verted  into  steam-engines,  by  reversing  the  motions,  and 
changing  the  resistance  for  the  power.  Some  rotative 
engines  have  been  constructed  on  the  principle  of  Bar- 
ker's mill  ;  others  have  been  made,  by  immersing  an 
overshot-wheel  in  a  cistern  of  heated  fluid,  either  water, 
oil,  or  melted  metal,  and  delivering  the  steam  under  the 
ascending  or  inverted  buckets  ;  so  that,  when  these  were 
filled  with  steam,  the  full  buckets,  on  the  opposite  side, 
might  preponderate,  and  cause  the  wheel  to  revolve. 
But,  in  general,  the  rotary  engines  hitherto  constructed, 
have  either  been  feeble  in  power,  or  encumbered  with 
excessive  friction,  on  account  of  the  extensive  packing, 
which  is  necessary,  to  keep  them  tight ;  so  that  none  of 
them  have  found  their  way  into  use.  It  is  probable,  that 
no  method  of  constructing  a  variable  cavity,  for  steam, 
which  is,  in  other  respects,  suitable,  affords  so  advantage- 
ous a  mode  of  applying  the  power,  as  the  cylinder  and 
piston,  producing  rectilinear  motion. 

Use  of  Steam  at  high  Temperatures. — Innon-conden- 


USE    OF  VAPORS    OF  LOW  TEMPERATURE.  127 

sing,  or  high-pressure  engines,  the  power,  which  is  conver- 
tible to  use,  consists  of  the  surplus  which  remains,  after 
overcoming  the  pressure  of  the  atmosphere.  Of  course, 
the  higher  is  the  temperature  at  which  the  steam  is  worked, 
the  greater  is  the  total  gain,  supposing  the  absorption 
of  heat,  and  the  production  of  power,  to  continue  to  take 
place,  in  equal  proportions.  This  consideration,  with  other 
expected  advantages,  has  given  rise  to  many  attempts  to 
improve  the  steam-engine,  by  devising  modes  of  applying 
steam,  at  much  higher  temperatures  than  those,  which  it 
has  been  ordinarily  found  practicable  to  employ.  At- 
tempts of  this  kind  have,  also,  frequently  been  founded 
upon  an  undue  estimate  of  the  elastic  force  of  steam,  at 
high  temperatures,  and  of  the  absorption  of  heat,  during 
its  production.  In  practice,  it  is  found  difficult  to  obtain 
a  material,  capable  of  confining  water  and  steam,  in  safety, 
w^hen  raised  to  such  a  temperature,  as  to  produce  a  pres- 
sure often,  or  more,  atmospheres  ;  since,  independently  of 
the  strain  upon  the  joinings,  the  cohesive  strength  of 
metals  is  diminished,  and  their  oxidation  promoted,  by 
exposure  to  great  heat. 

Use  of  Vapors  of  low  Temperature. — Certain  Hquids, 
such  as  alcohol,  ether,  sulphuret  of  carbon,  and  a  hquid, 
obtained  by  condensing  oil-gas,  have  been  proposed,  as 
substitutes  for  water,  in  producing  steam,  on  account  of 
the  low  temperature,  at  which  they  are  converted  into 
vapor.  Thus,  alcohol  boils  at  about  one  hundred  and 
seventy-three  degrees  of  Fahrenheit ;  sulphuric  ether,  at 
ninety-eight  degrees  ;  muriatic  ether,  at  fifty-one  degrees  ;* 
sulphuret  of  carbon,  at  one  hundred  and  sixteen  degrees  ; 
and  oil-gas  liquid,  at  one  hundred  and  eighty-six ;  all  of 
which  are  lower  than  the  boiling  point  of  water.  Some  of 
ihese,  when  raised  to  the  boihng  point  of  w^ater,  have  a 
much  greater  elastic  force  than  that  fluid.  Thus,  the  sul 
phuret  of  carbon,  at  two  hundred  and  twelve  degrees,  has 
an  elastic  force  equal  to  about  four  atmospheres,!  and  sul- 
phuric ether,  of  nearly  six  atmospheres.    But  these  advan  • 

*  Ure's  Dictionary. 

t  See  Tredgold's  Tables,  Steam  Engine,  p.  78—81. 


i^  MOVING  FORCES   USED  IN  THE   ARTS. 

tages  are  nearly  counterbalanced,  by  the  small  spaces 
through  which  these  vapors  act,  their  volume,  at  their 
boiling  point,  being  only  from  about  an  eighth  to  a  third 
part  of  that  of  steam,  at  the  boiling  point  of  vvater.  To 
this  disadvantage  may  be  added  the  expensive  character 
of  these  substances,  and  the  difficulty  of  condensing  them, 
without  loss,  in  any  working  engine.  Some  of  them,  hke- 
wise,  as  the  ethers,  act,  chemically,  upon  metals,  and 
could  not,  on  this  account,  be  employed  in  engines  made 
of  the  common  materials. 

Gas  Engines. — It  has  been  attempted  to  obtain  power 
for  propelling  machinery,  from  the  combustion,  or  explo- 
sion, of  inflammable  elastic  fluids,  such  as  coal-gas,  and 
the  vapor  of  combustible  liquids,  mixed  with  atmospheric 
air.  In  combustions  of  this  kind,  rarefaction,  and  sub- 
sequent condensation,  take  place,  which,  if  conducted 
within  suitable  cavities,  may  be  made  to  aflbrd  a  moving 
power,  applicable  to  machinery.  The  principal  engines, 
which  have  been  constructed,  for  using  this  power,  are 
those  of  Messrs.  Morey,  in  this  country,  and  iirown,  in 
England.  If  a  power  of  this  kind  could  be  made,  to  af- 
ford an  adequate  propelling  force  for  locomotive  engines, 
upon  public  roads,  it  would  possess  an  advantage,  in  the 
lightness  of  the  machinery,  compared  with  the  weiglit  of 
steam-engines,  with  their  water  and  fuel.  But  it  remains 
for  experience  to  determine,  whether  the  space,  through 
which  the  force  will  act,  taken  in  connexion  with  the  cost 
of  the  materials,  can  render  this  an  economical  source  of 
power. 

In  addition  to  the  foregoing  method  of  procuring  power, 
by  the  combustion  of  gases,  Sir  H.  Davy  has  proposed 
the  employment  of  certain  fluids,  which  are  volatile  at 
common  temperatures,  but  which  have  been  condensed 
iuto  liquids,  under  great  pressure,  such  as  carbonic  acid, 
ammonia,  &c.  His  views  are  founded  upon  the  immense 
'  difference  which  exists,  between  the  increase  of  elastic 
force  in  gases,  under  high,  and  low,  temperatures,  by  simi- 
lar increments  of  temperature.  But  doubts  have  been 
raised  upon  this  subject,  with  regard  to  the  space,  through 
which  the  force  of  these  gases  will  act,  and,  also^  in  regard 


STEAM-CARRIAGES. STEAM-GUN.  129 

to  the  quantity  of  heat,  requisite  to  produce  tne  change 
of  temperature  required.* 

Steam  Carriages. — It  has  long  been  a  favorite  object 
with  projectors,  to  construct  a  form  of  the  steam-engine, 
in  connexion  with  a  carriage,  which  should  be  capable  of 
propelling  itself  upon  the  public  roads.  Locomotive  en- 
gines are  capable  of  moving  themselves  upon  rail-roads, 
and  of  drawing  with  them  additional  loaded  carriages  ;  be- 
cause, in  this  case,  the  motion  is  uniform,  and  very  little 
of  the  power  is  expended,  in  surmounting  obstacles,  or 
changing  the  form  of  the  road.  But,  upon  a  pubHc  high- 
way, it  requires,  by  a  common  estimate,  about  eight  times 
as  much  power  to  propel  a  carriage,  as  it  does  upon  a 
rail-road.  Of  course,  the  weight  and  inertia  of  an  engine, 
capable  of  producing  this  power,  must  increase  somewhat 
in  the  same  proportion,  and  a  great  part  of  the  power  will 
become  necessary,  to  transport  the  machine  itself.  The 
inertia,  also,  will  be  continually  brought  into  unfavorable 
action,  by  the  jolts  and  concussions,  inseparable  from  high- 
way travelling,  and  thus  endanger  the  destruction  of  a  ma- 
chine, requiring  such  nice  adaptation  of  parts,  as  the  steam- 
engine.  It  appears,  that  steam-carriages  have  been  made 
to  run  upon  good  roads,  during  short  experiments,  while 
the  engine  was  new.  But  we  have  no  account,  as  yet, 
of  any  one  having  long  performed  this  kind  of  service. 

Steam  Gun. — Mr.  J.  Perkins, f  whose  experiments  on 
the  steam-engine  are  well  known,  has  attempted  the  em- 
ployment of  the  expansive  force  of  steam,  as  a  substitute 
for  gunpowder,  in  throwing  projectiles.  The  steam-gun, 
invented  by  him,  is  somewhat  similar,  in  its  construction, 
to  the  air-gun  ;  but  the  power  is  derived  from  a  magazine 
of  water,  heated  to  a  very  high  temperature  ;  so  that,  when 
portions  of  it  are  discharged  from  the  vessel  containing 
it,  they  produce  steam  enough  to  project  a  cannon  ball 
with  great  force.  The  balls  are  admitted  into  the  gun, 
in  succession,  from  a  hopper,  and  can  be  discnarged,  at 

*  Philosophical  Transactions,  1826,  Tredgold,  on  the  S  earn  Engine, 
p  84. 

t  The  public  are  indebted  to  Mr.  Perkins,  for  the  art  of  steel  eugrav- 
ing,  the  nail  machine,  and  many  other  useful  inventions. 


130  MOVING  FORCES  USED  IN  THE  ARTS. 

the  rate  of  twenty-four  in  a  minute.  It  appears,  from 
some  experiments  made  with  these  guns,  in  France,  that 
the  projectile  force  of  steam  is  greatly  inferior  to  that  of 
gunpowder ;  a  consequence,  no  doubt,  of  the  vast  differ- 
ence, which  is  known  to  exist,  in  the  initial  force  of  the 
two  agents  ;  nevertheless,  the  rapidity,  with  which  the  dis- 
charges may  be  made,  seems  capable  of  advantageous 
employment,  in  some  situations. 

GUNPOWDER. 

Manufacture. — Gunpowder  is  a  solid,  explosive,  mix- 
ture, composed  of  nitre,  sulphur,  and  charcoal,  reduced 
to  powder,  and  mixed  intimately  with  each  other.  The 
proportion  of  the  ingredients  varies,  very  considerably  ; 
but  good  gunpowder  may  be  composed  of  the  following 
proportions  ;  seventy-six  parts  of  nitre,  fifteen  of  char- 
coal, and  nine  of  sulphur,  equal  to  one  hundred.  These 
ingredients  are  first  reduced  to  a  fine  powder,  separate- 
ly, then  mixed,  intimately,  and  formed  into  a  thick  paste. 
This  is  done,  by  pounding  them,  for  a  long  time,  in  wood- 
en mortars,  at  the  same  time  moistening  them  with  water, 
to  prevent  the  danger  of  explosion.  The  more  intimate 
is  the  mixture,  the  better  is  the  powder  ;  for,  since  nitre 
does  not  detonate,  except  when  in  contact  with  inflamma 
ble  matter,  the  whole  detonation  will  be  more  speedy,  the 
more  numerous  the  surfaces  in  contact.  After  the  paste 
has  dried  a  little,  it  is  placed  upon  a  kind  of  sieve,  full  of 
small  holes,  through  which  it  is  forced.  By  that  process, 
it  is  divided  into  grains,  the  size  of  which  depends  upon 
the  size  of  the  holes,  through  which  they  have  passed. 

The  powder,  when  dry,  is  put  into  barrels,  which  are 
made  to  turn  round  on  their  axis.  By  this  motion,  the 
grains  of  gunpowder  rub  against  each  other,  their  asperi- 
ties are  worn  off,  and  their  surfaces  are  made  smooth. 
The  powder  is  then  said  to  be  glazed.  The  granulation 
and  glazing  of  the  powder  causes  it  to  explode  more 
quickly,  perhaps,  by  facihtating  the  passage  of  the  flame 
among  the  particles. 

Detonation. — When  gunpowder  comes  in  contact  with 
any  ignited  substance,  it  explodes,  as  is  well  known,  with 


FORCE.  131 

^reat  violence.  This  effect  may  take  place,  even  in  a 
vacuum.  A  vast  quantity  of  gas,  or  elastic  fluid,  is  emit- 
ted, the  sudden  production  of  which,  at  a  high  tempera- 
ture, is  the  cause  of  the  violent  effects  which  this  sub- 
stance produces.  The  combustion  is,  evidently,  owing  to 
the  decomposition  of  the  nitre,  by  the  charcoal  and  sulphur. 
The  products  are,  carbonic  oxide,  carbonic  acid,  nitro- 
gen, sulphurous  acid,  and,  probably,  sulphureted  hydro- 
gen. Mr.  Cruikshanks  has  ascertained,  that  no  percep- 
tible quantity  of  water  is  formed.  What  remains,  after 
the  combustion,  is  potash,  combined  with  a  small  portion 
of  carbonic  acid,  sulphate  of  potash,  a  very  small  propor- 
tion of  sulphuret  of  potash,  and  unconsumed  charcoal. 

Force. — The  elastic  fluid  which  is  generated,  when 
gunpowder  is  fired,  being  very  dense,  and  much  heated, 
begins  to  expand,  with  a  force,  at  least,  one  thousand  times 
greater  than  that  of  air,  under  the  ordinary  pressure  of 
the  atmosphere.  And,  allowing  the  pressure  of  the  at- 
mosphere to  be  fourteen  and  three  fourths  pounds,  upon 
every  square  inch,  the  initial  force,  or  pressure,  of  fired 
gunpowder,  will  be  equal  to,  at  least,  fourteen  thousand 
seven  hundred  and  fifty  pounds,  upon  every  square  inch 
of  the  surface  which  confines  it.  But  this  estimate,  which 
is  that  of  Mr.  Robins,  is  one  of  the  smallest  which  has 
been  made.  According  to  Bernoulli,  the  initial  elasticity, 
with  which  a  cannon  ball  is  impelled,  is,  at  least,  equal  to 
ten  thousand  times  the  pressure  of  the  atmosphere ;  and, 
from  Count  Rumford's  experiments,  it  appears  more  than 
three  times  gisater  than  this. 

Gunpowder,  on  account  of  its  expensiveness,  and  the 
suddenness  and  violence  of  its  action,  is  not  employed  as 
a  regular  moving  force,  for  machinery.  It  is  chiefly  ap- 
plied to  the  throwing  of  shot,  and  other  projectiles,  and 
the  blasting  of  rocks. 

When  a  ball  is  thrown  from  a  gun,  the  greatest  force  is 
applied  to  it,  by  each  particle,  at  the  moment  of  its  explo- 
sion. But,  since  the  ball  cannot,  at  once,  acquire  the 
same  velocity,  with  which  the  elastic  fluid,  if  at  liberty, 
would  expand,  it  continues  to  be  acted  upon  by  the  fluid, 
and  its  motion  is  accelerated,  in  common  cases,  until  it 


132      MOVING  FORCES  USED  IN  THE  ARTS. 

has  escaped  from  the  mouth  of  the  piece.  The  acceler 
ating  force,  however,  is  not  uniform  ;  and,  hence,  the  fol- 
lowing circumstances  deserve  attention.  1.  The  elasti- 
city is,  inversely,  as  the  space  which  the  fluid  occupies  ; 
and,  therefore,  as  it  forces  the  ball  out  of  the  gun,  it  con- 
tinually diminishes.  2.  The  elasticity  would  diminish,  in 
this  ratio,  even  if  the  temperature  remained  the  same  ; 
but  it  must  diminish,  in  a  much  greater  ratio,  because  a  re- 
duction of  temperature  takes  place,  both  from  the  disper- 
sion of  the  heat,  and  the  absorption  of  it,  by  the  fluid  it- 
self, during  its  rarefaction.  3.  The  fluid  propels  the  ball, 
by  following  it,  and  acts  with  a  force  that  is,  other  things 
being  equal,  proportionate  to  the  excess  of  its  velocity, 
above  the  velocity  of  the  ball.  The  greater  the  velocity 
that  the  ball  has  acquired,  the  less,  therefore,  is  its  mo- 
mentary acceleration.  4.  From  this  change  of  relative 
velocity,  there  must  be  a  period,  when  the  velocity  of  the 
ball  wull  exceed  that  of  the  elastic  fluid  ;  and,  therefore, 
the  proper  length  for  a  gun  must  be  that,  in  which  the  ball 
would  leave  the  mouth,  at  the  time  wdien  the  velocities 
are  equal ;  and  all  additional  length  of  the  piece,  beyond 
this,  can  only  serve  to  retard  the  ball,  both  by  friction, 
and  atmospheric  pressure. 

The  force  of  fired  gunpowder  is  found  to  be  very  near- 
ly proportionate  to  the  quantity  employed  ;  so  that,  if  we 
neglect  to  consider  the  resistance  of  the  atmosphere,  then 
the  height  to  which  the  ball  will  rise,  and  its  greatest  hor- 
izontal range,  must  be,  directly,  as  the  quantity  of  powder, 
and,  inversely,  as  the  weight  of  the  ball.  Count  Rum- 
ford,  however,  found,  that  the  same  quantity  of  powder 
exerted  somewhat  more  force  upon  a  large  ball,  than  on 
a  smaller  one. 

Properties  of  a  Gun. — The  essential  properties  of  a 
gun  are,  to  confine  the  elastic  fluid,  as  completely  as  pos- 
sible, and  to  direct  the  course  of  the  ball  to  a  rectilinear 
path  ;  and  hence  arises  the  necessity  of  an  accurate  bore. 
The  icindage^  or  space,  produced  by  the  difference  of 
diameter  between  the  ball  and  the  bore,  greatly  diminishes 
the  effect  of  the  powder,  by  allowing  a  part  of  the  elastic 
fluid  to  escape,  before  the  ball.     The  advantage  of  a  rifle 


PROPERTIES    OF  A  GUNc  133 

barrel  is  chiefly  derived  from  the  more  accurate  contaci 
of  the  ball  with  its  cavity.  When  the  tore  is  twisted,  it  is 
also  supposed  to  produce  a  rotation  of  the  ball  round  an 
axis,  in  the  direction  of  its  motion,  which  renders  it  less 
hable  to  deviate  from  its  path,  on  account  of  '"regularities 
in  the  resistance  of  the  air.  The  usual  charge  of  powder 
is  one  fifth,  or  one  sixth,  of  the  weight  of  the  ball  ;  and, 
for  battering,  one  third.  When  a  twenty-four  pounder 
is  fired,  with  two  thirds  of  its  weight  of  powder,  it  may  be 
thrown  about  four  miles  ;  the  distance  being  reduced,  by 
the  resistance  of  the  air,  to  about  one  fifth  of  that,  which 
it  would  describe,  if  thrown  in  a  vacuum.* 

It  is  certain,  that  the  grains  of  gunpowder  do  not  in- 
flame at  once,  but  that  the  inflammation  occupies  time,  in 
being  communicated  from  one  particle  to  another  ;  so  that 
they  act,  successively,  rather  than  simultaneously,  in  im- 
pelling the  ball.  This  circumstance  contributes,  greatly, 
to  the  safety  of  fire-arms  ;  for,  if  the  whole  charge  of 
powder  exploded  at  once,  the  piece  would  be  in  danger 
of  bursting,  before  the  inertia  of  the  ball  would  be  over- 
come. It  is  on  account  of  the  suddenness  of  their  deto- 
nation, that  the  various  fulminating  powders  are  inappli- 
cable to  use,  in  fire-arms.  The  bursting  of  a  gun  may  be 
occasioned,  by  the  defective  condition  of  the  metal,  the 
disproportionate  amount  of  the  charge,  the  adhesion  and 
inertia  of  the  shot,  or  the  inertia  of  some  other  body,  op- 
posing the  escape  of  the  charge.  It  is  from  this  last  cir 
cumstance,  that  a  gun  is  hable  to  burst,  if  fired  with  its 
muzzle  under  water. 

To  enable  gunpowder  to  exert  its  full  efi:ect,  the  pro- 
portions of  the  cavity  of  the  piece,  to  the  charge,  should 
be  such,  as  to  allow  all  the  grains  to  explode,  before  they 
leave  the  cavity  ;  and,  also,  to  permit  the  elastic  fluid  to 
expend  as  much  of  its  pressure,  as  is  capable  of  acceler- 
ating the  ball.  The  superiority  of  a  musket,  over  a  pis- 
tol, arises  from  its  prolonging  the  action  of  the  powder  in 
this  way.  But,  for  reasons  already  stated,  there  are  hm- 
its  to  the  length  of  the  barrel,  which  cannot  be  usefully 

*  Young's  Natural  Philosophy,  vol.  i  p.  350. 
II.  12  XII 


134  MOVING  FORCES  USED  IN  THE  ARTS. 

exceeded  ;  and  these  have  been  nearly  settled,  by  com- 
mon practice. 

Blasting. — The  splitting  of  rocks,  by  gunpowder,  is 
performed  by  drilling  holes,  to  a  certain  depth,  and  in- 
serting a  charge  of  powder,  at  the  bottom.  The  hole  is 
then  filled  up,  by  ramming  in  fragments  of  stone,  bricks, 
or  other  hard  substances,  keeping  in  a  steel  wire,  which  is 
afterwards  withdrawn,  to  furnish  a  passage  for  the  prim- 
ing, by  which  fire  is  communicated  to  the  charge.  To 
prevent  the  danger  of  a  spark,  copper  wire  is  often  used, 
instead  of  steel.  And,  to  prevent  the  small  fragments 
from  flying  about,  it  is  found  useful  to  cover  the  rocks 
with  brush-wood,  or  some  other  elastic  substance. 

Rocks  may  be  blasted,  at  a  considerable  depth  under 
water,  by  means  of  the  diving-bell,  which  enables  work- 
men to  drill  and  charge  them  in  safety.  In  the  method 
practised  at  How^th,  in  Ireland,  after  the  charge  is  insert- 
ed, a  tin  tube  is  carried  up  from  the  rock,  to  the  surface 
of  the  water.  It  is  kept  empty,  and  made  water-tight, 
by  screwing  the  joints  to  each  other,  as  the  bell  ascends. 
The  powder  is  ignited,  by  dropping  pieces  of  red-hot  iron, 
through  the  tube,  from  a  boat  at  the  surface.  When  the 
depth  exceeds  twelve  feet,  no  danger  or  inconvenience  is 
experienced  by  the  boats,  beyond  a  violent,  eruptive,  ebul- 
lition of  the  w^ater. 

Magnetic  Engines. — Since  the  discovery  of  electro- 
magnetism,  by  aid  of  which,  very  powerful  magnets  have 
been  obtained,  various  persons  have  introduced  machines, 
which  revolve,  and  act  upon  a  small  scale,  by  magnet- 
ic power.  But  a  radical  difficulty  has  hitherto  attended 
them,  that  the  magnetic  force  acts  at  distances,  so  ex- 
tremely small,  and  diminishes,  in  such  a  rapid  ratio,  as 
the  distance  increases,  that  these  machines  have  not  been 
found  convertible  to  any  very  important  use. 

Works  of  Reference. — Smeaton's  Miscellaneous  papers 
4to.  1814  ; — Robison's  Mechanical  Philosophy,  vols.  ii.  and  iii.  ; — 
Gregory's  Mechanics  ; — Brewster's  Ferguson's  Mechanics  ; — 
Nicholson's  Operative  Mechanic,  8vo.  ; — Farey's  Treatise  on  the 
Steam  Engine,  4to  1827  ;  this  is  the  most  extensive  work,  on  its  sub- 
ject ; — Tredgold,  on  the  Steam  Engine,  4to.  1828  ;  this  is  the  most 
philosophic  work,  on  the  subject  ; — Stuart,  on  the  Steam  Engine, 


ARTS    OF  CONVEYING  WATER.  135 

Svo.  1824  ; — ^Partixgdox,  on  the  Steam  Engine,  8vo.  1825  ; — . 
R,EiVwicK,  on  the  Steam  Engine,  Svo.  New  York,  1830  ; — Bossut, 
Traite  Theoretique  et  Experimental  d'  Hydrodynamique,  1771  ; — 
Dr  BuAT,  Traite  d'  Hydraulique,  &c.  1786,  &c.  ; — Playfair's 
Outlines  of  Natural  Philosophy,  Svo.  1819  ; — Ure's  Dictionary  of 
Chemistry  ; — Works  of  Coulomb,  Desaguliers,  De  La  Hire, 

DePARCIEUX,  HuTTON,  RoBIXS,  RuilFORD,  &c. 


CHAPTER  XVII. 

ARTS  OF  CONVEYING  WATER. 

Of  Conducting  Water,  Aqueducts,  Water  Pipes,  Friction  of  Pipes, 
Obstruction  of  Pipes,  Syphon.  Of  Raising  XFa/e/-,  Scoop  Wheel, 
Persian  Wheel,  Noria,  Rope  Pump,  Hydreole,  Archimedes'  Screw, 
Spiral  Pump,  Centrifugal  Pump,  Common  Pumps,  Forcing  Pump, 
Plunger  Pump,  De  La  Hire's  Pump,  Hydrostatic  Press,  Lifting  Pump, 
Bag  Pump,  Double-acting  Pump,  Rolling  Pump,  Eccentric  Pump, 
Arrangement  of  Pipes,  Chain  Pump,  Schemnitz  Vessels  or  Hunga- 
rian Machine,  Hero's  Fountain,  Atmospheric  Machines,  Hydraulic 
Ram.  Of  Projecting  Water,  Fountains,  Fire  Engines,  Throwincr 
Wheel. 

The  employment  of  water,  as  an  agent  for  producing 
motion,  has  already  been  considered.  It  remains  to  at- 
tend to  the  various  modes,  by  which  this  fluid  may  be 
conveyed,  from  one  place  to  another,  either  for  use  in  the 
arts,  or  for  apphcation  to  the  necessary  purposes  of  life. 
The  principal  circumstances  which  require  attention,  un- 
der this  head,  are  the  following.  1.  The  conducting  of 
water,  from  one  place  to  another,  having  the  same,  or  a 
lower,  level.  2.  The  raising  of  water,  to  a  higher  level. 
3    The  projection  of  water,  through  the  atmosphere. 

OF   CONDUCTING  WATER. 

Aqueducts. — When  water  flows  in  a  current,  or  stream, 
as  in  rivers  or  canals,  it  does  so  in  obedience  to  gravita- 
tion, and  in  consequence  of  the  surface  being  lower  at  the 
end  towards  which  it  is  flowing,  than  in  that  from  which 
it  proceeds.  Its  motions  are  governed  by  laws,  some- 
what different  from  those  of  sohd  bodies,  descending  upon 


136  ARTS   OF  COxWEYING  WATER. 

inclined  planes,  and  this  difference  is  owing  to  the  want 
of  cohesion  among  the  particles.  Instead  of  moving  si- 
multaneously, the  particles  continually  change  their  rela- 
tive position  ;  so  that,  while  one  portion  of  the  fluid  may 
be  moving  rapidly,  another  may  be  stationary,  or  even 
moving,  by  an  eddy,  in  a  contrary  direction.  The  motion, 
however,  will  continue,  both  in  open  channels,  and  in 
properly  constructed  pipes,  until  an  equilibrium  is  pro- 
duced, by  the  surface,  at  both  ends  of  the  channel, 
arriving  at  the  same  level.  Aqueducts  are  artificial  chan- 
nels, or  conduits,  for  the  conveyance  of  water,  in  a  hori- 
zontal, or  descending,  direction.  The  aqueducts,  con- 
structed by  the  ancient  Romans,  were  among  the  most 
costly  monuments  of  their  arts.  Several  of  these  were 
from  thirty  to  a  hundred  miles  in  length,  and  consisted  of 
vast  covered  canals,  built  of  stone.  They  were  carried 
over  valleys,  and  level  tracts  of  country,  upon  arcades, 
which  were  sometimes  of  stupendous  height  and  solidity. 
A  similar  method  has  been  practised,  in  some  modern 
cities,  of  warm,  or  temperate,  climates. 

In  colder  latitudes,  if  the  course  of  the  aqueduct  is 
above  the  ground,  the  water  is  liable  to  be  interrupted,  by 
freezing,  in  winter.  It  has,  therefore,  become  common, 
to  resort  to  subterranean  passages  for  water,  which  are 
placed  so  deep,  as  to  be  below  the  reach  of  frost,  and  are, 
also,  favorably  situated,  both  for  convenience  and  econ- 
omy. Culverts,  and  drains,  which  are  intended  merely 
to  remove  and  expend  Vv'ater,  are  usually  made  of  brick, 
or  stone  ;  but,  for  conveying  water  with  the  smallesl 
expenditure  by  loss,  icater-pipes  are  most  frequently  re- 
sorted to. 

Water  Pipes. — The  pipes,  by  which  water  is  conveyed 
beneath  the  ground,  are,  generally,  of  small,  or  moderate, 
size,  and  are  intended  to  be  water-tight.  In  consequence 
of  a  well-known  law  of  fluids,  a  water-pipe  may  possess 
any  degree  of  flexure,  and  any  number  of  curvatures,  be- 
low the  level  of  the  fountain-head  ;  yet,  if  it  be  not  ob- 
structed by  air,  or  any  other  internal  obstacle,  it  will  rise, 
at  the  discharging  end,  and  may  be  delivered,  at  the  height 
of  the  original  level.       Pipes,  for  transmitting  water,  have 


IRON  PIPES.  137 

been  made  from  a  great  variety  of  materials.*  It  is  desir- 
able that  they  should  possess  strength,  tightness,  and  du- 
rability, and  that  the  material,  of  which  they  are  composed, 
should  not  be  caj-able  of  contaminating  the  water.  Wood- 
en pipes  are,  commonly,  hollow  logs,  perforated,  by  bo'ring 
through  their  axis,  and  connected  together,  by  making  the 
end  of  one  log  conical,  and  inserting  it  into  a  conical  cav- 
ity in  the  next.  When  large  trunks  are  required,  they 
are  composed  of  thick  staves  and  hoops,  like  a  cask. 
They  should,  where  practicable,  be  imbedded  in  clay, 
and  buried  at  a  greater  depth,  than  the  frost  is  ever  know^n 
to  penetrate.  Wooden  pipes  are  in  common  use,  in  this 
country,  but  are  liable  to  decay,  especially  at  the  joints, 
where  their  thickness  is  smallest.  In  salt  marshes,  they 
are  more  durable,  though  still  liable  to  decay,  from  the 
attrition,  and  decomposing  effect,  of  the  water  within 
them. 

Iron  pipes  are,  at  the  present  day,  considered  prefera- 
ble to  those  of  wood,  being  stronger,  and,  in  most  situa- 
tions, more  durable.  They  are  made  of  cast-iron,  with 
a  socket,  or  enlarged  cavity,  at  one  end,  into  which  the 
end  of  the  next  pipe  is  received.  The  joints,  thus  form- 
ed, are  rendered  tight,  either  by  fiUing  the  interstices  with 
lead,  or  by  driving  in  a  small  quantity  of  hemp,  and  fill- 
ing the  remainder  of  the  socket  with  iron  cement,  made 
of  sulphur,  muriate  of  ammonia,  and  chippings  of  iron. 
Copper  pipes  are  extremely  durable,  and  are  made  of 
sheet  copper,  with  the  edge  turned  up,  and  soldered. 
They  require  to  be  tinned,  inside,  on  account  of  the  poison- 
ous character  of  some  of  the  compounds,  which  are  hable 
to  be  formed  in  them.  Lead  pipes  are  much  employed,  for 
small  aqueducts,  owing  to  the  facility  with  which  they  can 
be  soldered,  and  bent  in  any  direction.  They  are  com- 
monly cast  in  short  pieces,  and  afterwards  elongated,  by 
drawing  them  through  holes,  in  the  same  manner  as  wire. 
Leaden  pipes,  in  general,  are  supposed  not  to  contaminate 
the  water  contained  in  them^  because  the  carbonate  of 

*  It  appears,  that  the  use  of  water-pipes  was  not  unknown  to  the 
ancients.  Some  rules,  respecting  the  use  of  leaden  and  earthen  pipes 
are  given  by  Vitruvius  de  Architectura,  Lib.  viii. 

13* 


138  ARTS   OF  CONVEYING  WATER. 

lead,  which  is  sometimes  formed  in  them,  is  insoluble  in 
water.  They  are  not  safe,  however,  for  pumps  and  pipes, 
intended  to  convey  acid  liquors.  Stone  pipes  preserve 
the  water,  contained  by  them,  in  a  very  pure  state.  They 
are,  however,  expensive,  on  account  of  the  labor  of  work- 
ing them,  with  the  exception  of  soap-stone,  which,  being 
easily  shaped  and  bored,  may  be  usefully  appHed  to  the 
purpose  of  conveying  w^ater,  in  those  places  where  it  is 
easily  procured.  Earthen  pipes,  made  of  common  pottery 
ware,  and  glazed  on  the  inside,  are  sometimes  used,  but 
are  more  liable  to  be  broken,  than  most  of  the  other  kinds. 
Friction  of  Pipes. — In  a  river,  or  open  channel,  it  is 
observable,  that  the  water  flows  most  rapidly,  in  the  mid 
die  of  the  upper  surface,  while  it  is  most  retarded,  at  the 
edges,  and  at  the  bottom.  In  like  manner,  in  a  cylin- 
drical pipe,  the  fluid  has  the  greatest  velocity,  at  the  cen- 
tre, or  axis,  and  the  smallest  velocity,  at  the  surface,  or 
where  it  is  in  contact  with  the  pipe.  The  force,  by  w^hich 
this  retardation  is  occasioned,  is  commonly  called  fric- 
tion. It  differs,  in  many  respects,  from  the  friction  of 
solids  ;  and  more  resistance  is  occasioned,  by  the  internal 
action  of  the  fluid  particles  upon  each  other,  than  by  the 
contact  of  the  solid  surface,  in  which  they  are  contained. 
The  investigation  of  the  laws  which  govern  the  move- 
ments of  fluids  is  intricate,  and  the  results  of  experiment 
have  not  agreed  with  the  previous  conclusions  of  theory. 
Various  writers,  on  the  science  of  hydraulics,  have  treated 
this  subject  with  an  extensiveness  of  research,  which  can 
only  be  understood  from  their  own  works.  Among  the 
more  simple,  practical,  facts,  to  which  it  is  useful  to  at- 
tend, the  following  may  be  briefly  stated.  1.  The  veloci- 
ty of  water  is  greater  in  a  large  pipe,  than  in  a  small  one, 
having  the  same  position  ;  and  hence,  a  large  pipe  will 
discharge  more  water,  in  a  given  time,  than  a  number  of 
small  ones,  having,  jointly,  the  same  capacity.  A  pipe, 
of  two  inches  diameter,  will  give  more  water,  than  five 
pipes,  of  one  inch  diameter  ;  it  being  ascertained,  that  the 
squares  of  the  discharges  are,  very  nearly,  as  the  fifth  pow- 
ers of  the  diameters.*     2.  Irregularities  and  inequalities, 

*  Robison's  Mechcinical  Philosophy,  vol.  ii.  p   578. 


OBSTRUCTION  OF  PIPES.  139 

in  the  iiiameter  of  the  pipe,  dmiinish  the  amount  of  water 
which  they  transmit,  by  ahering  the  direction  of  the  par- 
ticles, and  by  changing  their  velocity,  so  as  to  renew  the 
resistance  of  inertia.  3.  In  like  manner,  all  curves  and 
angles,  which  occur  in  the  pipe,  have  a  similar  retard- 
ing effect,  by  creating  new  motions,  or  counter  currents. 
4.  The  form  of  the  end  of  the  pipe,  which  communicates 
with  the  fountain-head,  or  reservoir,  greatly  affects  the 
quantity  of  water  received  by  it.  If  it  be  gradually  en- 
larged, like  a  trumpet  mouth,  a  larger  quantity  of  water 
will  be  received,  than  by  any  of  the  modes  which  follow, 
because  the  direction,  given  to  the  particles  by  this  form, 
is  most  favorable  to  their  admvssion.  If  the  entrance  to 
the  pipe  be  abrupt,  in  consequence  of  the  cavity  being 
wholly  cylindrical,  the  particles  will  have  a  tendency  to 
cross  each  other,  and  less  water  will  enter  the  pipe,  in  a 
given  time.  And,  if  the  end  of  the  pipe  projects  into 
the  reservoir,  a  variety  of  opposing  forces  will  be  pro- 
duced, among  the  particles  moving  toward  the  entrance  ; 
so  that  a  smaller  quantity  will  be  received  by  the  pipe, 
than  in  either  of  the  preceding  cases. 

The  form  of  the  discharging  orifice,  also,  influences  the 
quantity  of  water  delivered  by  a  pipe,  in  a  given  time. 
If  the  end  of  the  pipe  be  enlarged,  by  adding  to  it  a  frus- 
tum of  a  hollow  cone,  the  amount  of  w^ater  discharged,  in 
some  cases,  may  be  prodigiously  increased.*  This  fact, 
described  by  Venturi,  appears  to  be  the  result  of  the 
pressure  of  the  atmosphere,  aided  by  the  inertia  and  co- 
hesiveness  of  the  water. 

Obstruction  of  Pipes. — Water  pipes  are  liable  to  be 
obstructed,  chiefly,  by  the  following  circumstances.  1. 
By  the  freezing  of  the  water,  in  winter,  if  the  pipe  has 
not  been  laid  sufiiciently  deep.  2.  By  the  deposition  of 
sand  and  mud,  in  the  low^er  parts  of  the  pipe.  To  obvi- 
ate this,  the  water  should  pass  through  a  strainer,  before 
it  enters  the  pipe.  And,  if  plugs  are  placed  at  the  lower 
parts  of  the  bendings,  then,  whenever  these  are  opened, 
the  water  rushes  out  with  sufficient  rapidity,  and  carries 

*  See  Edinburgh  Encyclopedia,  Art.  Hydrodynamics,  pp.  494,  495 


140  ARTS   OF  CONVEYING  WATER. 

the  deposition  with  it.  3.  By  the  penetratwn  of  rootj, 
or  the  growth  of  aquatic  vegetables,  in  the  cavity  of  the 
pipe  This  principally  happens  in  wooden  pipes,  after 
they  begin  to  decay.  4.  By  the  collection  of  air,  in  the 
upper  parts  of  the  bendings.  This  is  a  serious  evil,  and 
may  take  place  in  all  pipes,  which  have  an  undulating 
course,  or  more  vertical  curvatures  than  one.  When  air 
is  thus  confined  in  the  pipes,  the  water  will  not  rise  to  the 
same  height,  at  the  discharging  end,  as  at  the  fountain 
head.  The  air,  being  the  lighter  fluid,  tends  to  occupy 
the  highest  part  of  the  bendings.  Any  pressure,  applied 
at  the  fountain-head,  tends  to  push  this  air  a  little  beyond 
the  highest  part,  so  as  to  make  it  occupy  a  portion  of  the 
descending  side  of  the  curve.  Of  course,  the  sum  of  the 
weights,  in  the  descending  sides,  will  be  less  than  the  sum 
of  the  weights,  in  the  ascending  sides,  and  the  fluids  will 
not  be  in  equilibrium,  except  when  the  water,  at  the  foun- 
tain-head, is  higher  than  that  at  the  discharging  end.  The 
conditions,  upon  which  this  equilibrium  is  produced,  are 
the  same  as- those  which  sustain  the  fluid,  at  different  lev- 
els, in  Hero's  fountain,  the  spiral  pump,  and  the  hydro- 
static lamp. 

The  prevention  of  this  evil  consists,  in  avoiding  ver- 
tical curves,  and  in  laying  the  pipe,  if  possible,  w  ith  an 
uninterrupted  slope,  or,  at  least,  with  only  one  slope  in 
each  direction.  When  this  is  done,  the  air  will  escape 
at  one,  or  both,  ends  of  the  pipe.  But,  w^hen  vertical 
curves  are  unavoidable,  an  open  tube,  the  height  of  which 
is  equal  to  that  of  the  fountain-head,  should  be  attached 
to  the  highest  part  of  the  curve.  By  this  arrangement, 
the  air  will  readily  escape.  In  like  manner,  if  a  tight  air- 
box  be  fastened  upon  the  upper  part  of  the  curve,  and 
filled  with  water,  the  air  will  escape  into  this  box,  and 
displace  the  water,  without  interrupting  the  current  in  the 
pipe.  The  air-box  may  be  made  to  regulate  itself,  and 
to  discharge  the  air,  when  it  is  full,  by  means  of  a  valve 
in  the  top,  connected  with  a  floating,  hollow^,  copper  ball. 
As  the  air  increases,  the  copper  ball  will  subside  with  the 
water,  till  it  opens  the  valve,  for  the  air  to  escape.  In 
Fig.  160,  AB,  represents  an  undulating  pipe,  of  which 


141 


A,  is  the  fountain-head,  and  B,  the  discharging  end. 
The  water  and  air  will  arrange  themselves,  as  represented 
by  the  darker  and  lighter  parts  of  the  tube,  and,  being 
in  equilibrium,  no  water  will  be  discharged.  If  an  up- 
right tube,  C,  be  attached  to  either  of  the  upper  flex- 
ures, it  will  discharge  the  air  from  that  flexure.  Or,  if 
a  tight  box,  or  vessel,  D,  be  substituted,  with  a  copper 
float  and  valve,  it  will  have  a  similar  eflect.  Simple 
punctures,  made  in  the  upper  part  of  the  pipe,  also  answer 
a  temporary  purpose. 

Syphon. — The  syphon  may  be  regarded  as  an  instru- 
ment for  the  lateral  conveyance,  rather  than  the  rising,  of 
water  ;  since  the  fluid  must  always  be  delivered,  at  a  low- 
er level  than  that  at  which  it  is  received.  The  syphon 
is  a  bent  tube,  of  which  one  extremity,  or  leg,  is  longer 
than  the  other.  If  the  shorter  leg  be  inserted  in  a  fluid, 
and  the  air  be  exhausted  from  the  longer  leg,  by  suction, 
or  otherw^ise,  till  the  syphon  is  full  of  water,  then  the  col- 
umn of  fluid  in  the  longer  leg  will  preponderate,  and  the 
current  will  take  place.  This  will  continue,  either  till  the 
water,  in  the  feeding  vessel,  sinks  below^  the  end  of  the 
syphon,  or  that  in  the  receiving  vessel  rises  to  the  same 
height  with  the  other.  As  the  movement  depends  upon 
the  pressure  of  the  atmosphere,  water  cannot  be  raised, 
in  a  syphon,  to  a  greater  height  than  thirty-four  feet. 

For  practical  use,  the  longer  leg  of  the  syphon  is  often 
closed  with  a  stop-cock,  and  the  air  exhausted  from  it,  by 
a  small  pump,  till  the  leg  is  full.  The  stop-cock  is  then 
opened,  and  the  fluid  immediately  flows  through  the  sy- 
phon. 


1.4.2  ARTS  OF  CONVEYING  WATER. 


OF   RAISING  WATER. 

The  lateral  conveyance  of  water  is  effected,  in  the 
modes  already  described,  by  the  aid  of  its  own  gravity. 
The  raising  of  water  is  effected,  against  gravity,  by  the 
employment  of  some  moving  force.  Hydraulic  machines, 
for  raising  water,  may  be  impelled  by  a  current,  or  fall, 
of  the  water  itself,  or  by  any  other  moving  agent.  Among 
a  great  variety  of  machines,  which  have  been  constructed 
for  this  use,  the  following  are  some  of  the  most  noticeable. 

(Scoop  Wheel. — If  a  water-wheel  is  provided  with  a 
hollow  axle,  and  if,  in  the  place  of  spokes,  or  radii,  it  is 
furnished  with  crooked  tubes,  or  cavities,  of  a  suitable 
curvature,  it  will  raise  water  to  the  height  of  its  own  axis, 
whenever  it  revolves  in  the  direction  of  the  mouths  of 
the  tubes.  Each  spoke,  or  curved  tube,  as  it  dips  its 
extremity  in  the  water,  lifts  a  certain  portion  of  the  fluid  : 
and,  as  the  revolution  continues,  this  water  will  flow- 
through  the  tube,  approaching  nearer  to  the  axis,  until  it 
is  discharged  into  the  central  hollow.  To  prevent  the 
water  from  regurgitating,  the  inner  ends  of  the  tubes  must 
be  guarded  by  valves,  or  else  made  to  project,  for  a 
short  distance,  into  the  central  cavity,  as  seen  at  A,  in 
Fig.  161.     In  the  latter  case,  it  is  necessary,  that  thev 

Fig.  161. 


should  enter,  at  different  distances  from  the  end  of  the 
axle.  The  axle  may  also  be  divided  into  as  many  lon- 
gitudinal compartments,  as  there  are  tubes  in  the  wheel. 


PERSIAN  WHEEL. NORIA. ROPE   PUMP.         14^3 

This  was  done  in  the  ancient  tympanum,  a  machine  de- 
scribed by  Vitruvius,  which  was  somewhat  similar,  in  its 
principle,  to  the  scoop-wheel. 

Persian  Wheel. — The  Persian  wheel,  in  certam  re- 
spects, resembles  the  scoop-wheel,  and  is  sometimes 
combined  with  it,  in  the  same  machine.  It  differs  from  it, 
hi  its  effect,  by  raising  the  water  through  the  whole  di- 
ameter of  the  wheel.  Its  form  is  easily  understood,  by 
supposing  a  number  of  buckets  to  be  hung  round  the  cir- 
cumference of  a  water-wheel,  upon  pivots,  at  equal  dis- 
tances. As  the  wheel  turns,  the  buckets  are  successively 
immersed  in  the  water,  at  the  bottom,  and  filled.  They 
then  pass  upwards,  till  they  arrive  at  the  top  of  the  wheel, 
where  they  strike  a  fixed  obstacle,  and  are  overset,  dis- 
charging their  water  into  a  trough,  placed  at  the  top,  to 
receive  it.  This  machine  is  saidto  be-in  common  use, 
in  several  of  the  Oriental  countries. 

J^oria. — The  machine  used  in  Spain,  under  the  name 
of  noria,  consists  of  revolving  buckets,  like  the  Persian 
wheel.  But,  instead  of  a  single  wheel,  two  drums,  or 
trundles,  are  employed,  and  the  buckets  are  attached  to 
ropes,  or  chains,  passing  round  them.  In  Spain,  earthen 
pitchers  are  said  to  be  used;  but,  in  other  countries, 
wooden  buckets  are  employed,  like  those  of  an  over- 
shot-wheel.  A  sufficient  idea  of  the  form  of  the  noria 
may  be  obtained,  by  inspecting  the  figure  of  the  chain- 
wheel,  on  page  89,  and  supposing  the  motion  reversed. 

Rope  Pump. — Instead  of  a  series  of  buckets,  connec- 
ted by  ropes,  or  chains,  a  similar  effect  is,  sometimes,  pro- 
duced by  a  simple  rope,  or  a  tundle  of  ropes,  passing 
over  a  wheel  above,  and  a  pulley  below,  moving  with  a 
velocity  of  about  eight  or  ten  feet  in  a  second,  and  draw- 
ing up  a  certain  quantity  of  water,  by  its  friction.  It  is 
probable,  that  the  water  commonly  ascends,  with  about 
half  the  velocity  of  the  rope.  While  the  water  is,  prin- 
cipally, supported  by  the  friction  of  the  rope,  its  own  co 
hesion  is  sufficient  to  prevent  it  from  wholly  falling,  oi 
being  scattered,  by  any  accidental  inequality  of  the  mo 
tion.  The  portion  raised  is  collected  in  a  trough,  at 
the  top. 


144  ARTS    OF  CONVEYING  WATER. 

Hydreole. — This  name  is  given  by  M.  Mannoury 
Dectot,  to  an  invention  for  raising  water,  by  the  admix- 
ture of  atmospheric  air.  If  a  column  of  water  be  inti- 
mately mixed  with  air,  in  small  bubbles,  the  air  will  or 
cupy  some  time  in  ascending  to  the  surface;  and  the 
meanwhile,  the  collective  specific  gravity  of  the  whole 
colinnn  will  be  much  less,  than  if  it  consisted  of  water 
alone.  If  a  vertical  tube  be  placed  in  a  reservoir  of  wa- 
ter, and  if  a  quantity  of  air  be  injected  into  the  bottom  of 
the  tube,  by  a  bellows,  or  forcing  pump,  the  water  in  the 
tube  will  immediately  rise  to  a  higher  level,  and  remain, 
until  the  air  has  escaped  at  the  top.  And,  if  the  tube  be 
of  proper  height,  the  water  will  overflow,  in  the  same 
manner  as  it  does  during  the  ebullition  of  boihng  liquids. 
This  appears,  however,  not  to  be  a  very  economical  mode 
of  applying  force. 

Jlrchimedes''  Screw. — This  name  is  given  to  a  machine, 
formed  by  one  or  more  pipes,  wound  spirally  round  a 
cylinder,  which  revolves  on  an  axis,  in  an  oblique  situa- 
tion. It  is  used,  in  some  places,  under  the  name  of  wa- 
ter-snail. Its  mode  of  operation  may  be  easily  conceiv- 
ed, by  supposing  a  tube,  formed  into  a  hoop,  to  be  rolled 
up  an  inclined  plane,  in  which  case,  the  fluid  would  be 
forced,  by  the  elevation  of  the  tube  behind  it,  to  run,  as 
it  were,  up  hill.  The  screw  is  usually  turned,  by  a  water- 
wheel.  During  each  revolution,  the  lower  end  of  each 
spiral  tube  is  immersed  in  the  water,  and  dips  up  a  cer- 
tain quantity.  This  water,  by  its  gravity,  keeps  to  the 
lower  side  of  'lie  screw,,  as  seen  in  Fig.  162  ;  but,  at  the 

Fig.  162. 


WATER-SCREW. SPIRAL  PUMP.  145 

same  time,  in  consequence  of  the  revolutions  of  the  screw, 
it  passes  continually  upward,  until  it  is  delivered,  at  the 
highest  end. 

This  instrument  is  sometimes  made,  by  fixing  a  spiral 
partition  round  a  cylinder,  and  covering  it  with  an  exter- 
nal coating,  either  of  wood,  or  of  metal.  It  should  be 
so  placed,  with  respect  to  the  surface  of  the  water,  as  to 
fill,  in  each  turn,  one  half  of  a  convolution  ;  for,  when 
the  orifice  remains  always  immersed,  its  effect  is  much 
diminished.  It  is  generally  inclined  to  the  horizon,  in  an 
angle  of  between  forty-five  and  sixty  degrees  ;  hence  it 
is  obvious,  that  its  utility  is  limited  to  those  cases,  in 
which  the  water  is  only  to  be  raised  to  a  moderate  height. 
The  spiral  is  seldom  single,  but  usually  consists  of  three 
or  four  separate  coils,  forming  a  screw,  which  rises,  more 
rapidly,  round  the  cylinder. 

A  icater-screw,  which  operates  in  a  similar  manner, 
may  be  made,  by  a  spiral  partition,  wound  upon  a  central 
axis,  and  revolving,  by  itself,  within  a  smooth  hollow 
cylinder,  to  the  cavity  of  which  it  is  nearly  fitted.  In 
this  form,  however,  there  is  some  loss,  by  the  leakage 
between  the  screw,  and  the  cyHnder  which  contains  it. 

Spiral  Pump. — This  machine  is  formed,  by  a  spiral 
pipe,  consisting  of  many  convolutions,  arranged  either  in 
a  single  plane,  as  in  Fig.  163,  or  in  a  cylindrical,  or  con- 

Fi?.  163. 


ical,  surface,  and  revolving  round  a  horizontal  axis.  The 
pipe  is  connected,  at  one  end,  by  a  central  water-tight 
joint,  to  an  ascending  pipe,  while  the  other  end  receives, 
during  each  revolution,  nearly  equal  quantities  of  air  and 
II.  13  XII. 


146  ARTS  OF  CONVEYING  WATER. 

water.  It  was  invented,  about  1746,  by  Andrew  Wirtz, 
a  pewterer,  at  Zurich ;  whence  it  is  often  called  the  Zu- 
rich machine.  It  is  said  to  have  been  used,  with  great 
success,  at  Florence,  and  in  Russia.  Dr.  Young  states, 
that  he  has  made  use  of  it,  for  raising  water,  to  a  height 
of  forty  feet.  The  end  of  the  pipe  is  furnished  with  a 
spoon^  containing  as  much  water  as  will  fill  half  of  one  of 
its  coils.  The  water  enters  the  pipe,  a  httle  before  the 
spoon  has  arrived  at  its  highest  situation,  the  other  half 
remaining  full  of  air.  The  air  communicates  the  pres- 
sure of  the  column  of  water  to  the  preceding  portion  ; 
and,  in  this  manner,  the  efiect  of  nearly  all  the  water  in 
the  wheel  is  united,  and  becomes  capable  of  supporting 
the  column  of  w^ater,  or  of  water  mixed  with  air,  in  the 
ascending  pipe.  The  air,  nearest  the  joint,  is  compressed 
into  a  space,  much  smaller  than  that  which  it  occupied  at 
its  entrance  ;  so  that,  where  the  height  is  considerable,  it 
becomes  advisable  to  admit  a  larger  portion  of  air  than 
would,  naturally,  fill  half  the  coil.  This  lessens  the  quan- 
tity of  water  raised,  but  it  lessens,  also,  the  force  requir- 
ed to  turn  the  machine.  The  joint  should  be  conical,  in 
order  that  it  may  be  tightened,  when  it  becomes  loose  ; 
and  the  pressure  ought  to  be  removed  from  it,  as  much 
as  possible.  The  loss  of  power,  supposing  the  machine 
well  constructed,  arises  only  from  the  friction  of  the  wa- 
ter on  the  pipes,  and  the  friction  of  the  wheel  on  its  axis  ; 
and,  where  a  large  quantity  of  water  is  to  be  raised  to  a 
moderate  height,  both  of  these  resistances  may  be  ren- 
dered inconsiderable.  But,  when  the  height  is  very  great, 
the  length  of  the  spiral  must  be  much  increased,  so  that 
the  weight  of  the  pipe  becomes  extremely  cumbersome, 
and  causes  a  great  friction  on  the  axis,  as  well  as  a  strain 
on  the  machinery. 

Centrifugal  Pump. — The  centrifugal  force  has  some- 
times been  employed,  in  conjunction  with  the  pressure 
of  the  atmosphere,  as  an  immediate  agent,  in  raising  wa- 
ter, by  means  of  a  rotary  pump.  The  machine,  called 
centrifugal-pump,  consists  of  a  vertical  pipe,  capable  of 
revolving  round  its  axis,  and  connected,  above,  with  a  hor- 
izontal pipe,  which  is  open  at  one,  or  at  both,  ends  ;  the 


COMMON  PUMPS. 


147 


whole  being  furnished  with  proper  valves,  to  prevent  the 
escape  of  the  water,  when  the  machine  is  at  rest.  As 
soon"  as  the  rotation  becomes  sufficiently  rapid,  the  cen- 
trifugal force  of  the  water,  in  the  horizontal  pipe,  causes 
it  to  be  discharged,  at  the  ends,  its  place  being  supplied, 
by  means  of  the  pressure  of  the  atmosphere  on  the  reser- 
voir below,  which  forces  the  water  to  ascend,  through 
the  vertical  pipe.  This  machine  may  be  so  arranged, 
that,  according  to  theory,  very  Httle  of  the  force  applied 
is  lost ;  but  it  has  failed  of  producing,  in  practice,  a  very 
advantageous  effect.     In  Fig.  164,  a  centrifugal  pump  is 

Fig.  164. 


represented.  The  machine  is  first  filled  witn  water, 
through  the  funnel.  A,  while  the  valve,  at  D,  prevents  the 
water  from  descending.  The  whole  is  then  made  to 
turn  rapidly,  and  the  water  is  discharged,  from  the  ends 
of  the  horizontal  part,  into  a  circular  trough,  a  section  of 
which  is  seen  at  B,  and  C. 

Common  Pumps. — A  pump  is  a  machine,  so  well 
known,  and  so  generally  used,  that  the  denomination  has 
sometimes  been  extended  to  hydraulic  machines  of  all 
kinds.  The  term,  however,  in  its  strictest  sense,  is  to 
be  understood  of  those  machines,  in  which  the  water  is' 
raised,  by  the  motion  of  one  sohd  within  another  ;  and  this 
motion  is  usually  alternate,  but  sometimes  continued,  so 
as  to  constitute  a  rotatior.     In  the  pumps  most  com 


148 


ARTS   OF  CONVEYING  WATER. 


monly  used,  a  cavity  is  enlarged  and  contracted,  by  turns, 
the  water  being  admitted  into  it  through  one  valve,  and 
discharged  through  another. 

The  common  household-pump  has  otherwise  been  call- 
ed the  sucking-pump,  from  the  circumstance,  that  the 
water  is  raised  in  it,  by  the  pressure  of  the  atmosphere. 
In  this  country,  pumps  are  made  for  common  use,  both 
in  wells,  and  in  ships,  by  boring  logs,  so  as  to  produce  a 
large  hollow,  and  inserting  two  hollow  wooden  plugs,  cal- 
led boxeSj  at  different  heights,  both  of  which  are  furnish- 
ed with  valves,  or  clappers,  opening  upw^ards.  The 
lower  box  is  made  stationary,  and  serves  merely  to  pre- 
vent the  water,  which  is  raised,  from  running  back.  The 
upper  box  is  a  hollow  movable  piston,  attached,  by  its 
rod,  to  the  handle,  or  brake,  of  the  pump.  "When  the 
pump  is  full  of  water,  every  stroke  of  the  handle  raises 
this  box,  together  with  the  column  of  water  above  it. 
When  the  handle  is  hfted,  the  box  is  pushed  further  down 
hito  the  water,  while  its  valve  opens,  to  allow  the  w^ater 
to  pass  through.     In  Fig.  165,  this  pump  is  represented, 

Fig.  165. 


with  the  box  just  beginning  to  dtscend.  The  valve  then 
shuts,  and  the  second  stroke  of  the  pump  raises  another 
column  of  water  to  the  spout.  As  the  action  of  this 
pump  depends  upon  the  pressure  of  the  atmosphere,  wa- 


FORCING-PUMP. PLUNGER-PUMP. 


149 


ter  cannot  be  raised  by  it,  from  a  depth  of  more  than  thir- 
ty-four feet  below  the  upper  valve  ;  and,  in  practice,  a 
much  shorter  limit  is  commonly  assigned. 

Forcing  Pump. — The  forcing-pump  differs  from  the 
common  sucking-pump,  just  described,  in  having  a  sohd 
piston,  without  a  valve,  and  the  spout,  or  discharging 
orifice,  placed  below  the  piston.  When  the  piston  is 
raised,  the  lower  valve  of  the  pump  rises,  and  admits  the 
water  from  below,  as  in  the  common  pump.  But  when 
the  piston  is  depressed,  the  water  is  thrown  out,  through 
a  spout  in  the  side,  which  has  a  valve  opening  outward, 
at  [a,]  in  Fig.  166.     In  a  forcing-pump,  the  whaler  cannot 

Fiff.  166. 


be  brought  from  a  depth,  of  more  than  thirty-four  feet  be- 
low the  piston  ;  but  it  can  afterwards  be  sent  up,  to  any 
height  desired,  in  a  pipe,  [«t,]  because  the  pressure,  com- 
municated by  the  downward  stroke  of  the  piston,  is  not 
dependent  on  the  pressure  of  the  atmosphere,  but  upon 
the  direct  force  applied  to  the  piston. 

Plunger  Pump. — A  very  effectual  pump,  for  raising  a 
large  quantity  of  water,  to  a  small  height,  is  shown  in 
Fig.  167,  on  the  following  page. 

It  is  made,  by  fitting  two  upright  beams,  or  plungers, 
A  and  B,  of  equal  thickness,  throughout,  into  cavities, 
13* 


150 


ARTS   OF  CONVEYING  WATER. 
Fig.  167. 


nearly  of  the  same  size,  allowing  them  only  room  to  move 
without  friction,  and  connecting  the  plungers  together,  by 
a  horizontal  beam,  moving  on  a  pivot.  The  water  being 
admitted,  during  the  ascent  of  each  plunger,  by  a  large 
valve,  in  the  bottom  of  the  cavity,  at  C  and  D,  it  is 
forced,  when  the  plunger  descends,  to  escape  through  a 
second  valve,  at  E  or  F,  in  the  side  of  the  cavity,  and  to 
ascend,  by  a  wide  pipe,  to  the  top  of  the  machine.  The 
plungers  ought  not  to  be,  in  any  degree,  tapered  ;  be- 
cause, in  this  case,  a  great  force  would  be  unnecessarily 
consumed,  when  they  descend,  in  throwing  out  the  water, 
with  great  velocity,  from  the  interstice  formed  by  their 
elevation.  This  pump  may  be  worked  by  a  laborer, 
walking  backwards  and  forwards,  either  on  the  beam,  or 
on  a  board,  suspended  below  it.  By  means  of  an  ap- 
paratus of  this  kind,  described  by  Professor  Robison,  an 
active  man,  loaded  with  a  weight  of  thirty  pounds,  has 
been  able  to  raise  five  hundred  and  eighty  pounds  of  water, 
every  minute,  to  a  height  of  eleven  and  a  half  feet,  for 
ten  hours  a  day,  without  fatigue.  This,  says  Dr.  Young, 
is  the  greatest  effect  produced  by  a  laborer,  that  has  ever 
been  correctly  stated,  by  any  author  ;  it  is  equivalent  to 
somewhat  more  than  eleven  pounds,  raised  through  ten 
feet,  in  a  second,  instead  of  ten  pounds,  which  is  a  fair 
estimate  of  the  usual  force  of  a  man,  without  any  deduc- 
tion for  friction. 


OE  LA  hire's   pump. 


151 


i>6  Z^  Htrtrx  Pump. — A  pump,  partaking  of  the  nature 
til  a  forcing  and  a  sucking  pump,  is  sometimes  called  a 
mixed  pump.  In  De  La  Hire's  pump,  which  is  of  this  kind, 
and  shown  in  Fig.  168,  the  same  piston  is  made  to  serve 

Fig.  168. 


a  double  purpose  ;  the  rod  woiking  in  a  collar  of  leathers, 
and  the  water  being  admitted  and  expelled,  in  a  similar 
manner,  above  and  below  the  piston,  by  means  of  a  double 
apparatus  of  valves  and  pipes.  When  the  piston  is  de- 
pressed, the  water  enters  the  barrel  at  the  valve.  A,  and 
goes  out  at  B.  When  the  piston  is  elevated,  it  enters  at 
C,  and  escapes  at  D. 

For  forcing-pumps,  of  all  kinds,  the  common  piston, 
with  a  collar  of  loose  and  elastic  leather,  is  preferable  to 
those  of  a  more  complicated  structure.  The  pressure  of 
the  water,  on  the  inside  of  the  leather,  makes  it  sufficiently- 
tight,  and  the  friction  is  inconsiderable.  In  some  pumps, 
the  leather  is  omitted,  for  the  sake  of  simpHcity,  the  loss 
of  water  being  compensated  by  the  greater  durability  of 
the  pumps  ;  and  this  loss  will  be  the  smaller,  in  propor- 
tion, as  the  motion  of  the  piston  is  more  rapid. 

Hydrostatic  Press. — This  powerful  machine  is  essen- 
tially a  forcing-pump,  aided,  in  its  action,  by  the  well-known 
properties  of  hydrostatic  pressure.  It  appears  to  have 
been  invented  by  Pascal,  previously  to  1664,  and  recom- 
mended by  him,  as  a  new  mechanical  power.  It  was, 
however,  practically,  lost  sight  of,  till  it  was  re-invented  by 


152 


ARTS  OF  CONVEYING  WATER. 


Mr.  Bramah,  more  than  a  century  afterwards.  In  tlin 
press,  the  water  is  forced,  by  a  small  pump,  into  a  strong 
iron  cylinder,  in  which  it  acts  on  a  much  larger  piston  ; 
consequently,  this  piston  is  urged  by  a  force,  as  much 
greater  than  that  which  acts  on  the  first  pump-rod,  as  its 
surface  is  greater  than  that  of  the  small  one.  In  Fig. 
169,  the  water  is  forced,  by  the  pump.  A,  through  the 

Fig.  169. 

FrTnl rnpl. 


pipe,  B,  into  the  cylinder,  C,  in  which  it  acts,  very  pow- 
erfully, upon  the  large  piston,  D,  and  raises  the  bottom  of 
the  press,  E.  The  upward  force,  by  which  the  material, 
above  E,  is  compressed,  exceeds  the  force,  which  is  ap- 
plied to  the  pump,  as  much  as  the  surface  of  the  piston, 
D,  exceeds  that  of  the  piston  of  the  pump.  In  practice, 
the  cylinder,  C,  requires  to  be  made  much  thicker  than 
here  represented.- 

Lifting  Pump. — Where  the  height,  through  w^hich  the 
water  is  to  be  raised,  is  considerable,  some  inconvenience 
might  arise,  from  the  length  of  the  barrel,  through  which 
the  piston-rod  of  a  sucking-pump  would  have  to  descend, 
in  order  that  the  piston  might  remain  within  the  hmits  of 
atmospheric  pressure.  This  may  be  avoided,  by  placing 
the  movable  valve,  below  the  fixed  valve,  and  introducing 
the  piston,  at  the  bottom  of  the  barrel.  It  is  then  w^orked, 
by  means  of  a  frame,  on  the  outside.  Such  a  machine 
is  called  a  lifting-pump.  In  common  with  other  forcing- 
pumps,  It  has  the  disadvantage  of  thrusting  the  piston  be- 
fore the  rod,  and  thus  tending  to  bend  the  rod,  and  pro- 
duce an  unequal  friction  on  the  piston,  while,  in  the  suck- 


BA.a-PUMP. DOUBLE-ACTING  PUMP. 


153 


ing-pump,  the  principal  force  always  tends  to  straighten 
the  rod. 

Bag  Pump. — A  bag  of  leather  has  sometimes  been 
employed,  for  connecting  the  piston  of  a  pump  with  the 
barrel,  and,  in  this  manner,  nearly  all  friction  is  avoided. 
It  is  probable,  however,  that  the  want  of  durability  would 
be  a  great  objection  to  such  a  machine.    In  Fig.  170,  A, 


represents  a  leathern  bag,  attached  to  a  number  of  hoopb. 
This  bag  is  alternately  extended  and  contracted,  like  a 
bellows,  by  every  stroke  of  the  piston,  and  raises  the  wa- 
ter, without  friction  against  the  pump. 

Double-acting  Pump. — The  rod  of  a  sucking-pump, 
may  also  be  made  to  work  in  a  collar  of  leather,  at  the 
top,  as  at  A,  in  Fig.  171,  and  the  water  may  be  forced 

Fisr.  171. 


154  ARTS   OF  CONVEYING  WATER. 

through  a  valve,  into  an  ascending  pipe,  B.  By  applying 
an  air-vessel  to  this,  or  to  any  other,  forcing-pump,  as  is 
done  in  fire-engines,  its  motion  may  be  equalized,  and  its 
performance  improved  ;  for,  if  the  orifice  be  large  enough, 
the  water  may  be  forced  into  the  air-vessel,  during  the 
stroke  of  the  pump,  with  any  velocity  that  may  be  re- 
quired, and  with  little  resistance,  from  friction  ;  whereas, 
the  loss  of  force,  from  the  frequent  accelerations  and  re- 
tardations of  the  w^hole  body  of  water,  in  a  long  pipe, 
must  always  be  considerable.  The  condensed  air,  re- 
acting on  the  w^ater,  expels  it  more  gradually,  and  in  a 
continual  stream,  so  that  the  air-vessel  has  an  effect,  anal- 
ogous to  that  of  a  fly-wheel,  in  mechanics. 

Fig.  172. 


Rolling  Pump. — A  pump  of  this  kind  is  formed,  by  a 
bavrel,  or  hollow  cylinder,  shown  in  section,  in  Fig.  172, 
naving  two  partitions.  One  of  these,  iVB,  is  fixed,  and 
the  other,  CD,  is  composed  of  two  wings,  or  valves,  ca- 
pable of  an  alternate  motion,  about  the  axis  of  the  cylin- 
der. When  the  partition,  CD,  turns  in  one  direction, 
the  water,  in  the  cavity,  C,  is  driven  out  at  the  orifice,  [a,] 
and  will  rise  in  a  pipe,  attached  to  that  orifice.  At  the 
eane  time,  the  water,  in  the  cavity,  D,  is  forced  out  at 
the  orifice,  [d].  While  this  is  taking  place,  fresh  por- 
tions of  water  enter  the  remaining  cavities,  [at  mand  z]. 
When  the  partition,  CD,  has  moved,  as  far  as  possible,  it 
then  returns,  in  the  opposite  direction,  and  drives  out  the 
water,  through  [y  and  a;,]  and  receives  fresh  water, 
through  [b  and  c].  The  orifices,  which  receive  the 
water,  have  valves,  opening  inward,  and  those,  which  dis- 
charge it,  have  valves,  opening  outward.     The  machine 


ECCENTRIC-PUMP. 


155 


is  worked  by  arms,  attached  to  the  axis  of  the  cylinder, 
which,  for  this  purpose,  projects  through  a  collar,  in  the 
ends  of  the  vessel. 

For  the  sake  of  simplicity,  a  sector  of  a  cylinder  is 
sometimes  used  ;  in  which  case,  a  single  partition,  or 
valve,  like  a  door  on  hinges,  traverses  the  whole  cavity, 
and  only  half  the  number  of  orifices  are  necessary,  to  ad- 
;*.it  and  discharge  the  water.  Fire-engines,  for  project- 
ing water,  have  been  constructed,  in  byoih  these  methods, 
by  different  inventors. 

Fig.  173. 


Eccentric  Pump. — The  eccentric  pump,  a  section  of 
which  is  shown  at  Fig.  173,  consists  of  a  hollow  cylinder, 
[a(?,]  in  the  interior  of  which,  a  solid  cyhnder,  [6,]  of  the 
same  length,  but  of  about  half  the  diameter,  is  made  to 
revolve,  by  its  axle,  passing  through  water-tight  collars, 
in  the  ends  of  the  exterior  cylinder.  The  internal  cyl- 
inder is  so  placed,  that  its  surface  comes  in  contact  with 
some  part  of  the  internal  surface  of  the  larger  cylinder. 
The  surface  of  the  small  cylinder,  is  also  furnished  with 
four  large  valves,  or  flaps,  turning  on  hinges,  and  par- 
takir.g  of  its  own  curvature  ;  so  that,  when  they  are,  shut 
down,  they  form  no  projections,  but  appear  as  parts  of 
the  same  cylinder.  These  valves  are  made  to  open,  by 
springs,  or  otherwise  ;  so  that,  when  one  of  them  is 
brought,  by  the  revolution  of  the  internal  cylinder,  into 
the  narrowest  part  of  the  internal  space,  it  is  pressed 
down,  and  shut ;  but,  as  the  inner  cylinder  moves  on,  tha 


156  ARTS   OF  CONVEYING  WATER. 

valve,  being  gradually  carried  forward,  will  continue  to 
open,  until  it  arrives  at  the  widest  part  of  the  cavity.  It 
is  then  pressed  down  again,  by  a  continuation  of  the  rev- 
olution. In  this  way,  the  water  behind  the  valve  is  drawn 
up,  from  the  feeding-pipe,  by  the  atmospheric  pressure, 
while  that  before  the  valve  is  forced  upward,  into  the 
delivering  pipe.  As  each  of  the  valves  performs  the 
same  operation,  in  its  turn,  this  pump  affords  a  constant 
supply  of  water. 

Rotative  steam-engines  have  been  constructed,  by  dif- 
ferent projectors,  on  the  principle  of  this  pump,  as  well 
as  the  following. 

Fig.  174. 


Another  form  of  an  eccentric  pump,  is  seen  in  Fig. 
174.  The  roller,  or  solid  cylinder.  A,  revolving  within 
the  reservoir,  or  hollow  cylinder,  BF,  carries  with  it  the 
slider,  DE,  which  is  made  to  sweep  the  internal  surface 
of  this  cyhnder,  by  revolving,  in  the  direction  from  C  to 
F,  so  that  the  water  is  drawn  up,  by  the  pipe,  C,  and  dis- 
charged, by  the  pipe,  F. 

An  objection  to  all  pumps  of  this  sort  is,  that,  if  they 
are  made  tight  enough  to  hold  water,  they  occasion  a 
great  degree  of  friction,  on  account  of  the  extensive  con- 
tact.of  the  moving  surfaces.  The  continual  change,  also, 
which  takes  place,  both  in  the  direction  and  velocity  of 
the  water,  is  productive  of  great  resistance  from  inertia. 
The  stream,  at  the  delivering  orifice,  although  never  whol- 
ly intermitted,  is,  by  no  means,  uniform  in  its  velocity. 

Arrangement  of  Pipes. — The  pipes,  through  which  wa- 
ter is  raised,  by  pumps  of  any  kind,  ought  to  be  as  short, 
and  as  straight,  as  possible.     Thus,  if  we  have  to  raise 


CHAIN-PUMP,   ETC.  157 

water,  to  a  height  of  twenty  feet,  and  to  carry  it,  to  a  hor- 
izontal distance  of  one  hundred,  by  means  of  a  forcing- 
pump,  it  will  be  more  advantageous  to  raise  it  first,  ver- 
tically, into  a  cistern,  twenty  feet  above  the  reservoir, 
and  then  to  let  it  run  along  horizontally,  or  find  its  level  in 
a  bent  pipe,  than  to  connect  the  pump  immediately  with  a 
single  pipe,  carried  to  the  place  of  its  destination.  And, 
for  the  same  reason,  a  sucking-pump  should  be  placed  as 
nearly  over  the  well  as  possible,  in  order  to  avoid  a  loss 
of  force,  in  working  it.  If  very  small  pipes  are  used,  they 
will  much  increase  the  resistance,  by  the  friction  which 
they  occasion. 

Chain  Pump. — Water  has  sometimes  been  raised  by 
stuffed  cushions,  or  by  oval  blocks  of  wood,  connected 
with  an  endless  rope,  or  chain,  and  caused,  by  means  of 
two  wheels,  or  drums,  to  rise,  in  succession,  in  the  same 
oarrel,  carrying  the  water  in  a  continual  stream  before 
them.  The  magnitude,  however,  of  the  friction,  appears 
to  be  an  objection  to  this  method.  From  the  resemblance 
of  the  apparatus  to  a  string  of  beads,  it  has  been  called  a 
bead-pump^  or  paternoster-work.  When  flat  boards  are 
united  by  chains,  and  employed,  instead  of  these  cushions, 
the  machine  has  been  denominated  a  cellular  pump  ;  and, 
in  this  case,  the  barrel  is  usually  square,  and  placed  in 
an  inclined  position.  There  is,  however,  a  considerable 
loss,  from  the  facility  with  which  the  water  runs  back. 
The  chain-pump,  used  in  the  Navy,  is  a  pump  of  this 
kind,  with  an  upright  barrel,  through  which  leathers,  strung 
on  a  chain,  are  drawn  in  constant  succession.  These 
pumps  are  only  employed,  when  a  large  quantity  of  water 
is  to  be  raised,  and  they  must  be  w^orked  with  considera- 
ble velocity,  in  order  to  produce  any  effect  at  all. 

The  Chinese  work  their  cellular  pumps,  or  bead- 
pumps,  by  walking  on  bars,  which  project  from  the  axis 
of  the  wheel,  or  drum,  that  drives  them  ;  and,  whatever 
objection  may  be  made  to  the  choice  of  the  machine,  the 
mode  of  communicating  motion  to  it,  must  be  allowed  to 
be  advantageous. 

Schemnitz    Vessels,   or   Hungarian  Machine. — The 
mediation  of  a  portion  of  air  is  employed  for  raising  wa- 
ll. 14  XII. 


158 


ARTS   OF  CONVEYING  WATER. 


ter,  not  only  in  the  spiral-pump,  but  also  in  the  air-ves- 
sels of  Schemnitz,  in  the  manner,  shown  in  Fig.  175.     A 


column  of  water,  descending  through  a  pipe,  C,  into  a 
closed  reservoir,  B,  containing  air,  obliges  the  air  to  act, 
by  means  of  a  pipe,  D,  leading  from  the  upper  part  of 
the  reservoir,  or  air-vessel,  on  the  water  in  a  second  res- 
ervoir, A,  at  any  distance,  either  below  or  above  it,  and 
forces  this  water  to  ascend,  through  a  third  pipe,  E,  to 
any  height  less  than  that  of  the  first  column.  The  air- 
vessel  is  then  emptied,  the  second  reservoir  filled,  and 
the  whole  operation  repeated.  The  air  must,  however, 
acquire  a  density,  equivalent  to  the  pressure,  before  it  can 
begin  to  act ;  so  that,  if  the  height  of  the  columns  were 
thirty-four  feet,  it  must  be  reduced  to  half  its  dimensions, 
before  any  water  would  be  raised  ;  and  thus,  half  of  the 
force  would  be  lost.  But,  where  the  height  is  small,  the 
force  lost  in  this  manner  is  not  greater,  than  that  which  is 
usually  spent  in  overcoming  friction,  and  other  imperfec- 
tions, of  the  machinery  employed  ;  for  the  quantity  of 
water,  actually  raised  by  any  machine,  is  not  often  greater 
than  half  the  power  which  is  consumed.  The  force  of 
the  tide,  or  of  a  river,  rising  and  falling  with  the  tide, 
might  easily  be  applied,  by  a  machine  of  this  kind,  to  the 
purpose  of  raising  water.     Thus,  if,  at  low  tide,  the  ves- 


HERO   S   FOUNTAIN,   ETC 


159 


sel,  A,  was  filled  with  air,  then,  at  high  tide,  the  w^ater, 
dewing  down  the  tube,  E,  would  cause  the  water  in  the 
vessel,  B,  to  ascend  in  the  pipe,  C. 

Heroes  Fountain, — The  fountain  of  Hero,  precisely  re- 
sembles, in  its  operation,  the  hydrauHc  vessels  of  Schem- 
nitz,  which  were  probably  suggested  to  their  inventor,  by 
(he  construction  of  this  fountain.  It  may  be  used,  simply, 
to  raise  water,  or  to  project  it  upwards,  in  the  form  of  a 
pt,  as  in  Fig.  176.      The  first  reservoir,  C,  of  the  foun- 

Fig.  176. 


tain,  is  lowe^  'han  the  orifice  of  the  jet.  A  pipe  descends 
horn  it,  to  the  air-vessel,  B,  which  is  at  some  distance 
below,  and  the  pressure  of  the  air  is  communicated,  by 
dn  ascending  tube,  D,  to  a  third  cavity.  A,  containing  the 
water  which  supplies  the  jet.  1r  this  form  of  the  ma 
chine,  the  water  will  continue  to  spout  from  the  pipe,  E, 
sintil  all  the  water  in  the  reservoir,  C,  has  descended  into 
the  vessel,  B.  The  principle  of  Hero's  fountain  has 
been  applied,  to  raise  oil  in  lampi- ;  and  one  of  its  most 
simple  forms  has  already  been  desofibed,  under  the  head 
of  Hydrostatic  Lamp,,  page  334,  vol.  I. 

Atmospheric  Machines. — The  spontaneous  vicissitudes 
of  the  pressure  of  the  air,  occasioned  by  changes  in  the 
weight  and  temperature  of  the  atmosphere,  have  been  ap- 
plied, by  means  of  a  series  of  reservoirs,  furnished  wit^ 
proper  valves,  to  the  purpose  of  raising  water,  by  degrees, 
to  a  moderate  height.     But  it  seldom  happens,  that  such 


160 


ARTS   OF  CONVEYING  WATER. 


changes  are  capable  of  producing  an  elevation  m  the 
water  of  each  reservoir,  of  more  than  a  few  inches,  or, 
at  most,  a  foot  or  two,  in  a  day ;  and  the  whole  quantity 
raised  must  therefore  be  inconsiderable. 

Hydraulic  jRam.— The  momentum  of  a  stream  of  wa- 
ter, flowing  through  a  long  pipe,  has  also  been  employed, 
for  raising  a  small  quantity  of  water,  to  a  considerable 
height.  The  passage  of  the  pipe,  being  stopped  by  a 
valve  which  is  raised  by  the  stream,  as  soon  as  its  mo- 
tion becomes  sufficiently  rapid,  the  whole  column  of  fluid 
must  necessarily  concentrate  its  action,  almost  instantan- 
eously, on  the  valve.  In  this  manner,  it  loses  the  charac- 
teristic property  of  hydraulic  pressure,  and  acts,  as  if  it 
were  a  single  solid  ;  so  that,  supposing  the  pipe  to  be  per- 
fectly elastic,  and  inextensible,  the  impulse  may  overcome 
any  pressure,  however  great,  that  might  be  opposed  to  it. 
If  the  valve  opens  into  a  pipe,  leading  to  an  air-vessel,  a 
certain  quantity  of  the  water  will  be  forced  in,  so  as  to 
condense  the  air,  more  or  less  rapidly,  to  the  degree  that 
may  be  required,  for  raising  a  portion  of  the  water,  con- 
tained in  it,  to  a  given  height.  Mr.  Whitehurst  appears 
to  have  been  the  first  that  employed  this  method.  It  was 
afterwards  improved  by  Mr.  Boulton ;  and  the  same  ma- 
chine has  attracted  much  attention,  in  France,  under  the 
denomination  of  the  hydraulic  ram  of  M.  Montgolfier. 

Fig.  177. 


Fig.  177,  represents  this  machine.  When  the  water  in 
the  pipe,  AB,  has  acquired  sufficient  velocity,  it  raises 
the  valve,  B,  which  immediately  stops  its  further  passage. 
The  momentum,  which  the  water  has  acquired,  will  ther 


OF  PROJECTING  WATER. FOUNTAINS.  161 

force  a  portion  of  it,  through  the  valve,  C,  into  the  air- 
vessel,  D.  The  condensed  air,  at  D,  causes  the  water  to 
rise  into  the  pipe,  E,  as  long  as  the  effect  of  the  horizon- 
tal column  continues.  When  the  water  becomes  quies- 
cent, the  valve,  B,  will  open  again,  by  its  own  weight,  and 
the  current  will  be  renewed,  until  it  acquires  force  enough 
to  shut  the  valve,  and  repeat  the  operation. 

OF  PROJECTING  WATER. 

If  a  degree  of  force,  or  pressure,  be  applied  to  water, 
sufficient  to  raise  it,  through  a  tube,  to  a  given  height,  the 
same  force  would  also  cause  it  to  spout  through  an  ori- 
fice, in  a  continued  stream,  or  jet,  to  nearly  the  same 
height,  in  common  cases.  The  height,  however,  can 
never  be  fully  as  great,  for  various  reasons.  One  of 
these  is  found,  in  the  friction  of  the  ajutage,  or  discharg- 
ing orifice,  which  acts  as  a  retarding  force.  Another 
obstacle  is,  the  resistance  of  the  atmosphere,  which  in- 
creases, in  a  rapid  ratio,  as  the  velocity  of  the  water  be- 
comes greater,  and  which  is  also  greatly  augmented,  as 
the  w^ater  divides,  and  spreads  out  a  greater  surface  to 
the  resistance  of  the  air.  A  third  obstacle  consists,  in 
the  resistance  which  the  water  offers  to  itself.  The  parts 
first  projected,  being  constantly  retarded  in  their  ascent, 
by  gravity,  and  atmospheric  resistance,  oppose  the  pro- 
gress of  the  parts,  which  are  last  projected,  and  which 
have  the  greatest  velocity.  And,  as  fluids  move,  in  all 
directions,  this  impulse,  of  different  parts  of  the  water, 
against  each  other,  tends  to  widen,  and,  consequently,  to 
shorten,  the  column.  In  a  vertical  jet,  moreover,  the 
weight  of  the  falling  water  opposes  the  ascending  col- 
umn ;  and,  hence,  a  fluid  will  spout  higher,  if  the  jet  be 
turned  a  little  to  one  side,  than  if  it  be  perpendicular. 

Fountains. — Artificial  fountains,  which  throw  a  per- 
petual jet  of  water,  usually  act  by  the  pressure  of  a  res- 
ervoir of  water,  situated  at  a  greater  height  than  that  of 
the  jet  produced.  The  w^ater  is  conveyed  from  the  res 
ervoir,  to  the  place  of  the  fountain,  in  pipes  ;  and,  if  the 
orifice,  from  which  it  issues,  be  directed  upward,  it  will 
spout,  to  a  height  approaching  tnat  of  the  reservoir.  Ii 
14* 


162  ARTS   OF  CONVEYING  WATER. 

will  always,  however,  fall  short  of  this  height,  for  the 
reasons  already  stated  ;  and  the  difference  will  be  great- 
er, in  jets  of  great  height,  than  it  is  in  lower  ones  ;  since 
it  is  found,  by  experiment,  that  the  differences  between 
the  heights  of  the  jets  and  of  the  reservoirs,  are  as  the 
squares  of  the  heights  of  the  jets  themselves.*  Foun- 
tains are  chiefly  used,  for  purposes  of  ornament,  and,  when 
of  large  size,  require  to  be  fed  from  the  elevated  parts 
of  rivers,  or  bodies  of  water,  having  a  high  level.  At 
Peterhoff,  in  Russia,  there  are  two  fountains,  which  spout 
a  column  of  water,  nine  inches  in  diameter,  to  the  height 
of  sixty  feet,  and  the  fall  of  the  returning  water  produces 
a  concussion,  sufficient  to  shake  the  ground. 

Fire  Engines: — The  engines  used  for  extinguishing 
fires,  in  buildings,  are,  in  effect,  a  species  of  forcing 
pumps,  in  which  the  water  is  subjected  to  pressure  suffi- 
ciently strong  to  raise  it,  by  a  jet,  or  otherwise,  to-  the  re- 
quired height.  But,  if  the  forcing  pump  were  used  alone, 
the  water  would  issue  only  in  intermitting  jets,  in  conse- 
quence of  the  reciprocating  motion  of  the  pump,  and 
thus,  a  great  part  of  it  would  become  ineffectual.  In  or- 
der to  make  the  discharge  uniform,  and  thus  keep  up  a 
continual  stream,  a  strong  vessel,  filled  with  air,  is  at- 
tached to  the  engine.  Into  this  vessel,  the  water  is  forced, 
by  the  pumps  ;  and,  as  the  air  cannot  escape,  it  is  con- 
densed, in  proportion  as  the  water  accumulates,  until  it 
reacts  upon  the  surface  of  the  water,  with  great  power. 
If  the  air  be  condensed,  into  half  the  space  which  it  orig- 
inally occupied,  it  will  act  upon  the  water  with  a  pressure, 
equal  to  that  of  two  atmospheres,  and  will  be  adequate 
to  raise  water,  through  a  tube,  to  the  height  of  thirty-three 
feet,  or  to  project  it,  through  the  atmosphere,  to  nearly 
the  same  height.  When  the  air  is  condensed,  to  one 
third  of  its  former  volume,  in  consequence  of  the  air- 
vessel  being  two  thirds  filled  with  water,  its  elasticity  will 
be  three  times  greater  than  that  of  the  atmosphere.  It 
will  therefore  raise  water,  in  a  tube,  to  the  height  of  six- 
ty-six feet,  and  would  throw,  it  to  nearly  the  same  height, 

*  Ascertained  by  Mariotte. — Bossut,  Tom.  ii   §  615. 


THROWING-WHEEL.  163 

were  it  not  for  the  resistances,  which  have  already  been 
explained. 

The  foregoing  principle  of  the  fire-engine  has  been 
variously  modified,  by  adapting  different  kinds  of  pumps 
to  the  air-vessel,  and  by  altering  various  details.  In  the 
engines  of  Newsham,  and  others,  two  cylinders,  con- 
structed like  forcing-pumps,  are  worked  by  the  recipro- 
cating motions  of  transverse  levers,  to  which  the  handles 
are  attached.  In  this  way,  the  water  is  forced  into  the 
air-vessel,  from  which  it  afterwards  spouts,  through  a 
movable  pipe.  In  some  other  engines,  a  single  cylin- 
der is  used,  the  piston-rod  passing  through  a  tight  collar, 
as  it  does  in  Watt's  steam-engine,  thus  alternately  receiv- 
ing and  expelling  the  water,  at  each  end  of  the  cylinder. 
In  Rowntree's  engine,  and  some  others,  a  mechanism  is 
used,  hke  that  of  the  rolHng-pump,  a  part  of  the  inside  of 
a  cylinder  being  traversed  by  a  partition,  like  a  door, 
hinged  upon  the  axis  of  the  cylinder,  which  drives  the 
water,  successively,  from  each  side  of  the  cyhnder,  into 
the  air  vessel. 

A  long  flexible  tube,  made  of  leather,  and  known 
among  firemen  by  the  name  of  hose,  is  of  great  use  in 
carrying  the  spouting  orifice  near  to  the  flames,  and  thus 
preventing  the  water  from  being  scattered  too  soon.  It 
also  serves  an  important  purpose,  in  bringing  water  from 
distant  reservoirs,  by  suction,  created  in  the  pumps  of 
the  engine. 

Throioing  Wheel. — A  throwing-wheel,  otherwise  call- 
ed a  flash-wheel,  or  fen-wheel,  is  used  for  raising  water, 
both  by  lifting  and  projecting  it.  Its  structure  resembles 
that  of  an  undershot  water-wheel,  or,  more  properly,  of 
a  breast-wheel.  Its  under  surface  is  received  in  a  trough, 
or  channel,  which  curves  upward.  When  the  wheel  is 
made  to  revolve,  it  drives  the  water  before  it,  and  throws 
it  out  from  the  trough,  at  a  considerable  elevation.  These 
wheels  are  used,  for  draining  ponds,  marshes,  &c.,  and 
are  turned  by  wind-mills,  or  any  other  power.  If  their 
movement  is  slow,  they  simply  lift  the  water,  and  cause 
it  to  overflow,  at  the  end  of  the  trough.     But,  if  they 


164  COMBINING  FLEXIBLE   FIBRES. 

revolve  vv'th  much  velocity,  they  are  capable  of  throw- 
ing the  water  to  a  still  higher  level. 

VV^ORKs  OF  Reference. — Robison's  Mechanical  Philosophy,  ar- 
ticles. Theory  of  Rivers,  Water  Works,  &ic.; — Gregory's  Mechan- 
ics, vol.  i. ; — Young's  Natural  Philosophy,  vol.  i.; — Ilydraulia,  or  an 
Account  of  the  Water  Works  of  London,  8vo.  1835  ; — Bossut,  Traitc 
Theoretique  et  Experimental  d^  Hydrodynumique,  1771,  &c. ; — Du 
BuAT  Trait'ed^  Hydravlique,  et  Pyrodynamiquc,  1786,  &c.; — Ven- 
TURi,  Rlcherches  Experimentales  sur  Ics  Fluides,  1797; — Rees' 
Cyclopedia,  article  Water; — Edinburgh  Encyclopedia,  article  Hydro- 
dynamics ; — and  the  Hydraulic  Works  of  Mariotte,  Guglielmi- 
Ni,  MiCHALOTTi,  D.  and  J.  Bernoulli,  D'  Alembert,  Fon- 
TANA,  M.  Young,  Prony,  Vince,  Juan,  Eytelwein,  &c. 


CHAPTER  XVIII. 

ARTS  OF  COMBINING  FLEXIBLE  FIBRES. 

Theory  of  Twisting,  Rope  Making,  Hemp  Spinning.  Cotton  Man 
nfacture.  Elementary  Inventions,  Batting,  Carding,  Drawing,  Rov- 
ing, Spinning,  Mule  Spinning,  Warping,  Dressing,  Weaving,  Twil- 
ling, Double  Weaving,  Cross  Weaving,  Lace,  Carpeting,  Tapestry, 
Velvets,  Linens.  Woollens.  Felting.  Paper  Making.  Book- 
binding. 

Theory  of  Tivisting. — The  strength  of  cordage,  which 
is  employed  in  uniting  bodies,  and  the  utility  of  flexible 
textures,  which  serve  for  furniture,  or  for  clothing,  de- 
pend, principally,  upon  the  friction,  or  lateral  adhesion, 
produced  by  the  twisting  and  intermixture  of  their  constit- 
uent fibres. 

A  twisting  cord  is  not  so  strong  as  the  fibres  which 
compose  it,  supposing  the  fibres  and  cord  to  be  of  the 
same  length.  The  object  of  twisting  is,  to  connect  sue 
cessive  numbers  of  short  fibres,  in  such  a  manner,  that 
besides  the  mutual  pressure  which  their  own  elasticity 
causes  them  to  exert,  any  additional  force,  applied  in  the 
direction  of  the  length  of  the  aggregate,  may  tend  to  bring 
their  parts  into  closer  contact,  and  augment  their  adhesion 
.0  each  other.      The  simple  art  of  tying  a  knot,  and  the 


ROPE-MAKING.  165 

more  complicated  processes  of  spinning,  rope-making, 
weaving,  and  felting,  derive  most  of  their  utility  from  this 
principle. 

By  considering  the  effect  of  a  force,  which  is  counter- 
acted by  other  forces,  acting  obliquely,  it  will  be  seen, 
that  the  operation  of  twisting  has  a  useful  effect,  in  bind- 
ing the  parts  of  a  rope,  or  thread,  together  ;  and  also,  that 
it  has  an  inconvenience,  in  causing  the  strength  of  the 
fibres  to  act  with  a  mechanical  disadvantage.  The  great- 
er is  the  obliquity  of  the  fibres,  the  greater  will  be  their 
adhesion  to  each  other,  but  the  greater,  also,  will  be  their 
immediate  strain,  or  tension,  when  a  force  acts  upon  them, 
in  the  direction  of  the  whole  cord.  From  this,  it  follows, 
that,  after  employing  as  much  obliquity,  and  as  much  ten- 
sion, as  is  sufficient  to  connect  the  fibres  firmly  together, 
all  that  is  superfluously  added  tends  to  w-eaken  the  cord, 
by  overpowering  the  primitive  cohesion  of  the  fibres,  in 
the  direction  of  their  length. 

The  mechanism  of  simple  spinning  is  easily  understood. 
Care  is  taken,  where  the  hand  is  employed,  to  intermix 
the  fibres  sufficiently,  and  to  engage  their  extremities,  as 
much  as  possible,  in  the  centre  ;  for,  it  is  obvious,  that,  if 
any  fibre  were  wholly  external  to  the  rest,  it  could  not  be 
retained  in  the  yarn.  In  general,  however,  the  materials 
are,  previously,  in  such  a  state  of  intermixture,  as  to  ren- 
der this  precaution  unnecessary. 

Rope  Making. — A  single  thread  of  yarn,  consisting  of 
fibres  twisted  together,  has  a  tendency  to  untwist  itself, 
the  external  parts  being  strained,  by  extension,  and  the 
internal  parts,  by  compression  ;  so  that  the  elasticity  of  all 
the  parts  resists,  and  tends  to  restore  the  thread  to  its 
natural  state.  But,  if  two  such  threads,  similarly  twisted, 
are  retained  in  contact,  at  a  given  point  of  the  circumfer- 
ence of  each,  this  point  is  rendered  stationary,  by  the 
opposition  of  the  equal  forces,  acting  in  contrary  direc- 
tions, and  becomes  the  centre,  round  which  both  threads 
are  carried,  by  the  forces  which  remain  ;  so  that  they  con- 
tinue to  twist  round  each  other,  till  the  new  combination 
causes  a  tension,  capable  of  counterbalancing  the  remain- 
ing tension  of  the  original  threads.     Three,  four,  or  more, 


166  COMBINING  FLEXIBLE   FIBRES. 

threads  may  be  united,  nearly  in  the  same  manner.  A 
strand^  as  it  is  called  by  rope-makers,  consists  of  a  con- 
siderable number  of  yarns,  thus  twisted  together,  gener- 
ally from  sixteen  to  twenty-five  ;  a  halser  consists  of  three 
strands  ;  a  shroud^  of  four  ;  and  a  cable^  of  three  halsers, 
or  shrouds.  Shroud-laid  cordage  has  the  disadvantage 
of  being  hollow  in  the  centre,  or  else  of  requiring  a  great 
change  of  form  in  the  strands,  to  fill  up  the  vacuity  ;  so 
that,  in  undergoing  this  change,  the  cordage  stretches, 
and  is  unequally  strained.  The  relative  position,  and  the 
comparative  tension,  of  all  the  fibres,  in  these  complicated 
combinations,  are  not  very  easily  determined  by  calcula- 
tion ;  but,  it  is  found,  by  experience,  to  be  most  advan- 
tageous for  the  strength  of  ropes,  to  twist  the  strands, 
when  they  are  to  be  compounded,  in  such  a  direction,  as 
to  untw^ist  the  yarns,  of  w^hich  they  are  formed  ;  that  is,  to 
increase  the  twist  of  the  strands  themselves  ;  and,  proba- 
bly, the  greatest  strength  is  obtained,  when  the  ultimate 
obhquity  of  the  constituent  fibres  is  least,  and  the  most 
equable.* 

A  very  strong  rope  may,  also,  be  made,  by  twisting 
five  or  six  strands  round  a  seventh,  as  an  axis.  In  this 
case,  the  central  strand,  or  heart,  is  found,  after  much 
use,  to  be  chafed  to  oakum.  •  Such  ropes  are,  however, 
considered  unfit  for  rigging,  or  for  any  use,  in  which  they 
are  liable  to  be  frequently  bent. 

Ropes  are  most  commonly  made  of  hemp  ;  but  various 
other  vegetables  are  occasionally  employed.  The  Chi- 
nese even  use  w^oody  fibres  ;  and  the  barks  of  trees  fur- 
nish cordage  to  other  nations.  In  spinning  the  yarn,  in 
the  piocess  of  rope-making,  the  hemp  is  fastened  round 
the  waist  of  the  workman  ;  one  end  of  it  is  attached  to  a 
wheel,  turned  by  an  assistant,  and  the  spinner,  walking 
backwards,  draws  out  the  fibres  with  his  hands.  When 
one  length  of  the  walk  has  been  spun,  it  is  immediately 
reeled,  to  prevent  its  untwisting.  The  machines,  employ- 
ed in  continuing  the  process  of  rope-making,  are  mostly 
of  simple  construction  ;  but  both  skill  and  attention  are 

*  Young's  Natural  Philosophy,  vol.  i.  Lect.  xvi. 


HEMP-SPINNING. COTTON  MANUFACTURE.      167 

required,  in  applying  them,  so  as  to  produce  an  equable 
texture,  in  every  part  of  the  rope.  The  tendency  of  two 
strands  to  twist,  in  consequence  of  the  tension,  arising  from 
the  original  twist  of  the  yarns,  is  not  sufficient  to  produce 
^n  equilibrium,  because  of  the  friction  and  rigidity  to  be 
overcome.  Hence,  it  is  necessary  to  employ  force,  to 
assist  this  tendency,  and  the  strands,  or  ropes,  will  after- 
wards retain,  spontaneously,  the  form  which  has  thus  been 
given  them.  The  largest  ropes,  even,  require  external 
force,  in  order  to  make  them  twist  at  all. 

The  constituent  ropes  of  a  common  cable,  w^hen  sepa 
rate,  are  stronger  than  the  cable,  in  the  proportion  of  about 
four  to  three  ;  and  a  rope,  worked  up  from  yarns,  one  hun- 
dred and  eighty  yards  in  length,  to  one  hundred  and  thirty- 
five  yards,  has  been  found  to  be  stronger,  than  when  reduc- 
ed to  one  hundred  and  twenty  yards,  in  the  ratio  of  six  to 
five.  The  difference  is  owing,  partly,  to  the  obliquity  of 
the  fibres,  and,  partly,  to  the  unequal  tension,  produced 
by  twisting.* 

Hemp  Spinning. — The  desideratum  of  spinning  hemp, 
by  machinery,  has  been  attained  by  Mr.  Treadwell,  in  his 
machines  for  that  purpose,  now  at  work,  at  the  Charles- 
town  Navy  Yard,  and  elsewhere.  By  this  invention,  the 
hemp  is  drawn  out  to  the  requisite  size,  by  a  long  series 
of  teeth,  fixed  upon  a  revolving  belt,  and  afterwards  twist- 
ed, by  the  revolutions  of  the  machine.  The  equality,  or 
uniform  size,  of  the  yarn,  is  ensured,  by  a  roller,  or  small 
wheel,  which  rests  upon  the  part  just  twisted,  and  which 
rises,  or  is  pushed  up,  if  the  twist  becomes  too  large,  and 
moves  a  comb,  which  immediately  falls,  and  intercepts 
the  superfluous  part  of  the  fibres.  On  the  other  hand,  if 
the  twist  becomes  too  small,  the  roller  descends,  and,  in 
so  doing,  increases  the  rapidity  of  the  machine,  and  causes 
it  to  supply  the  hemp  faster. 

COTTON  MANUFACTURE. 

When  the  fibres  of  cotton,  wool,  or  flax,  are  intended 
to  be  woven,  they  are  reduced  to  fine  threads,  of  uniform 

*  Young's  Natural  Philosophy,  vol.  i.  Lect.  xvL 


168  COxMBINING  FLEXIBLE   FIBRES. 

Size,  by  the  well-known  process  o(  spinning.  Previous- 
ly to  the  middle  ot  the  last  century,  this  process  was  per- 
formed by  hand,  with  the  aid  of  the  common  spinning- 
wheel.  Locks  of  cotton,  or  wool,  previously  carded, 
were  attached  to  a  rapidly-revolving  spindle,  driven  by 
a  large  wheel,  and  were  stretched  or  draw^n  out  by  the 
hand,  at.  the  same  time  that  they  were  twisted  by  the 
spindle,  upon  which  they  were  afterwards  wound.  Flax, 
the  fibres  of  which  are  longer,  and  more  parallel,  was 
loosely  wound  upon  a  distaft',  from  which  the  fibres  were 
selected,  and  drawn  out  by  the  thumb  and  finger,  and,  at 
the  same  time,  were  twisted  by  flyers,  and  wound  upon 
a  bobbin,  which  revolved  with  a  velocity,  somewhat  less 
than  that  of  the  flyers. 

The  manufacture  of  flexible  stufls,  by  means  of  machin- 
ery, operating  on  a  large  scale,  is  an  invention  of  the  last 
century.  Ahhough  of  recent  date,  it  has  given  birth  to 
some  of  the  most  elaborate  and  wonderful  combinations 
of  mechanism,  and  already  constitutes,  especially  in  Eng- 
land, and  in  this  country,  an  important  source  of  national 
wealth  and  prosperity. 

Elementary  Inventions. — The  character  of  the  machin- 
ery which  has  been  applied  to  the  manufacture  of  cotton, 
at  different  times,  has  been  various.  There  are,  howev- 
er, several  leading  inventions,  upon  which  most  of  the 
essential  processes  are  founded,  and  which  have  given  to 
their  authors  a  greater  share  of  celebrity  than  the  rest. 
These  are,  1.  The  spinning-jenny.  This  machine  was 
invented  by  James  Hargreaves,*  in  1767,  and,  in  its 
simplest  form,  resembled  a  number  of  spindles,  turned  by 
a  common  wheel,  or  cylinder,  which  was  worked  by 
hand.  It  stretched  out  the  threads,  as  in  common  spin- 
ning of  carded  cotton.  2.  The  water  spinning-frame^ 
'nvented  by  Richard  Arkwright,  in  1769.  The  essen- 
tial, and  most  important,  feature  in  this  invention  con- 
sists in  the  drawing  out,  or  elongating,  of  the  cotton,  by 
causing  it  to  pass  between  successive  pairs  of  rollers, 
which  revolve,  with  different  velocities,  and  which  act  as 

*  Mr.  Guest,  in  a  late  work,  attributes  the  invention,  botli  of  the  jen- 
»y,  and  water  spinning-frame,  to  Thomas  Highs,  of  Leigh,  England 


BATTING.  169 

substitutes  for  the  finger  and  thumb,  as  applied  in  common 
spinning.  These  rollers  are  combined  with  the  spindle 
and  flyers  of  the  common  flax  wheel.  3.  The  mule. 
This  was  invented  by  Samuel  Crompton,  in  1779.  It 
combines  the  principles  of  the  two  preceding  inventions, 
and  produces  finer  yarn,  than  that  which  is  spun  in  either 
of  the  other  machines.  It  has  now  nearly  superseded 
the  jenny.  4.  The  power-loom  for  weaving,  by  water  or 
steam  power,  which  was  introduced  about  the  end  of  the 
eighteenth  century,  and  has  received  various  modifica- 
tions. 

The  foregoing  fundamental  machines  are  used  in  the 
same,  or  different  establishments,  and  for  different  pur- 
poses. But,  besides  these,  various  auxiliary  machines  are 
necessary,  to  perform  intermediate  operations,  and  to  pre- 
pare the  material,  as  it  passes  from  one  stage  of  the  man- 
ufacture to  another.  The  number  of  these  machines,  and 
the  changes,  and  improvements,  which  have  been  made  in 
their  construction,  from  time  to  time,  render  it  impossible 
to  convey,  in  a  work  hke  the  present,  any  accurate  idea 
of  their  formation,  in  detail.  A  brief  view,  however,  of 
the  offices  which  they  severally  perform,  may  be  taken,  by 
following  the  raw  material,  through  the  principal  changes 
which  it  undergoes,  in  a  modern  cotton-factory,  founded 
and  improved  upon  the  general  principles  of  Arkwright. 

Batting. — The  cotton,  after  having  been  cleared  from 
its  seeds,  at  the  plantation,  by  the  operation  of  ginning., 
described  on  page  111,  Vol.  I.,  is  compressed  into  b^gs, 
for  exportation,  and  arrives  at  the  factory,  in  a  dense  and 
matted  mass.  The  first  operation  to  which  it  is  submitted 
has,  for  its  object,  to  disentangle  the  fibres,  and  restore  the 
cotton  to  a  light,  open,  and  uniform,  state.  For  this  pur- 
pose, after  being  weighed  out,  it  is  submitted  to  the  ope- 
ration of  a  machine,  called  a  picker.,  or  of  another,  de- 
nominated a  batter.  In  some  of  these  machines,  it  is 
subjected  to  the  action  of  a  series  of  pins  ;  in  others,  to  a 
sort  of  blunt  knives,  revolving  with  great  rapidity  ;  the 
effect  of  which  is,  to  beat  up  and  separate  the  fibres,  to 
disengage  their  unequal  adhesionS;  and  to  reduce  the  whole 
to  a  very  light,  uniform,  flocculent,  mass. 

II.  In  XII. 


170  COMBINING  FLEXIBLE   FIBRES. 

Carding. — The  cotton  next  passes  to  the  carding-ma- 
chines,  of  which,  when  there  are  two,  the  first  is  called 
the  breaker,  and  the  second,  ihe  finisher.  In  this  opera- 
tion, the  cotton  is  carried  over  the  surface  of  a  revolving 
cylinder,  which  is  covered  with  card-teeth  of  wire,  and 
which  passes  in  contact  with  an  arch,  or  part  of  a  con- 
cave cylinder,  similarly  covered  with  teeth.  From  this 
cylinder,  it  is  taken  off  by  another,  called  the  doffing  cyl- 
inder, which  revolves  in  an  opposite  direction  ;  and  from 
this,  it  is  again  removed,  by  the  rapid  vibrating  movement 
of  a  transverse  comb,  otherwise  called  the  doffing -plate, 
moved  by  cranks.  It  then  exists  in  the  state  of  a  flat, 
uniform,  fleece,  or  lap,  which,  after  passing  the  breaker, 
undergoes  the  process  of  plying,  or  doubling,  by  causing 
it  to  perform  a  certain  number  of  revolutions  upon  a  cyl- 
inder, or  a  perpetual  cloth.  It  is  then  carded  a  second 
time,  by  the  finisher,  and  the  fleece,  after  being  taken  off 
from  this  machine,  is  draw^n  by  rollers,  through  a  hollow 
cone,  or  trumpet  mouth,  which  contracts  it  to  a  narrow 
band,  or  sliver,  and  leaves  it  coiled  up  in  a  tin  can,  ready 
for  the  next  operation.  The  process  of  carding  serves  to 
equalize  the  substance  of  the  cotton,  and  to  lay  its  fibres 
somewhat  in  a  more  parallel  direction. 

Drawing. — The  slivers  of  cotton  are  next  elongated, 
by  the  process  of  drawing.  This  operation  is  the  ground- 
work, or  principle,  of  Arkwright's  invention,  and  is  used 
in  the  roving,  and  spinning,  as  well  as  in  the  drawing- 
frame.  It  is  an  imitation  of  what  is  done  by  the  finger 
and  thumb,  in  spinning  by  hand,  and  is  performed,  by 
means  of  two  pairs  of  rollers.  The  upper  roller,  of  the 
first  pair,  is  covered  with  leather,  w^hich,  being  an  elastic 
substance,  is  pressed,  by  means  of  a  spring,  or  weight. 
The  lower  roller,  made  of  metal,  is  fluted,  in  order  to 
keep  a  firm  hold  of  the  fibres  of  cotton.  Another  similar 
pair  of  rollers  are  placed  near  those  which  have  been  de- 
scribed. The  second  pair,  moving  with  a  greater  veloc- 
ity, pull  out  the  fibres  of  cotton  from  the  first  pair  of  rol- 
lers. If  the  surface  of  the  last  pair  move  at  twice,  or 
thrice,  the  velocity  of  the  first  pair,  the  cotton  will  be 
di-awn  twice,  or  thrice,  finer  than  it  was  before.     Thij 


ROVING.  171 

relative  velocity  is  called  the  draught  ot  the  machine, 
This  mechanism  being  understood,  it  will  be  easy  to  con- 
ceive the  nature  of  the  operation  of  the  drawing-frame. 
Several  of  the  narrow  ribands,  or  slivers,  from  the  cards, 
(sometimes  termed  card-ends ,)  by  being  passed  through 
a  system  of  rollers,  are  thereby  reduced  in  size.  By 
means  of  a  detached,  single  pair  of  rollers,  the  several  re- 
duced ribands  are  pliedj  or  united  into  one  sliver. 

The  operations  of  drawing  and  plying  serve  to  equalize, 
still  further,  the  body  of  cotton,  and  to  bring  its  fibres 
more  into  a  longitudinal  direction.  These  slivers  are 
again  combined,  and  drawn  out,  so  that  one  sliver  of  the 
finished  drawing  contains  many  phes  of  card-ends.  Hith- 
erto, the  cotton  has  acquired  no  twist,  but  is  received  into 
movable  tin  cans,  or  canisters,  similar  to  those  used  for 
receiving  the  cotton  from  the  cards. 

Roving. — The  operation  of  roving  communicates  the 
first  twist  to  the  cotton.  It  is  performed  by  a  machine, 
called  the  roving-frame ^  or  double-speeder.  The  tin  cans, 
containing  the  shvers  of  cotton,  are  placed  upon  this  ma- 
chine, and  are  made  to  revolve,  slowly,  about  their  axes, 
so  as  to  produce  a  shght  degree  of  twisting.  The  slivers 
then  pass  again,  through  several  pairs  of  rollers,  moving 
with  different  speeds,  and  are  thus  still  further  attenuated, 
by  drawing.  They  are  then  slightly  spun,  by  the  revolu- 
tion of  flyers,  and  are  wound  upon  the  bobbins  of  the 
spindles,  in  the  form  of  a  loose,  soft,  imperfect,  thi-ead, 
denominated  the  roving. 

The  mechanism  of  the  double  speeder  is  complicated, 
and  interesting,  and  great  ingenuity  has  been  displayed,  in 
overcoming  the  difficulties  of  hs  construction.     In  order 
that  the  yarn,  or  roving,  may  be  wound  upon  the  bobbins, 
in  even,  cylindrical,  layers,  it  is  necessary,  that  the  spindle 
rail,  or  horizontal  bar,  which  supports  the  spindles,  should 
continually  rise  and  fall,  with  a  slow  alternate  motion 
This  is  effected  by  heart-wheels,  or  cams,  in  the  interio* 
of  the  machine.     Again,  since  the  collective  size  of  tht 
Dobbin  is  augmented,  by  the  addition  of  each  layer  oi 
roving,  it  is  obvious,  that,  if  the  axis  of  the  bobbin  re 
volved,  always,  with  the  same  velocity,  the  thread  of  rov 


172  COMBINING  FLEXIBLE   FIBRES. 

ing  would  be  broken,  in  consequence  of  being  wound  up 
too  fast.  To  prevent  this  accident,  the  velocity  of  the 
spindles,  and,  likewise,  the  motion  of  the  spindle-rail,  is 
obliged  gradually  to  diminish,  from  the  beginning  to  the 
end  of  an  operation.  This  diminution  of  speed  is  effect- 
ed, by  transmitting  the  motion,  both  to  the  spindle-rail, 
and  to  the  bobbins,  through  two  opposite  cones,  one  of 
which  drives  the  other  with  a  band,  the  band  being  made 
to  pass,  slowly,  from  one  end  to  the  other  of  the  cones, 
and  thus  continually  to  alter  their  relative  speed,  and 
cause  a  uniform  retardation  of  the  velocity  of  the  moving 
parts.*  As  the  roving  is  not  strong  enough  to  bear  any 
violence,  the  spindles,  which  support  the  bobbins,  are 
geared  to  each  other,  so  as  to  prevent  any  deviation  from 
the  proper  velocity. 

A  more  simple  form  of  the  roving-frame  has  been  in- 
vented,! in  which  the  gearing  is  dispensed  with,  as  well 
as  the  pair  of  cones,  which  regulates  the  motion  of  the 
bobbins.  In  this  machine,  the  bobbins  are  not  turned  by 
the  rotation  of  their  axes,  but  by  friction,  applied  to  their 
surface,  by  small  wooden  cylinders  which  revolve  in  con- 
tact with  them.  In  this  way,  the  velocity  of  the  surface 
of  the  bobbin  will  always  be  the  same,  whatever  may  be 
its  growth,  from  the  accumulation  of  roving,  so  that  the 
winding  goes  on,  at  an  equable  rate.  To  prevent  the  rov- 
ing from  being  stretched,  or  broken,  in  its  passage  from 
the  drawing  rollers  to  the  bobbins,  it  is  made  to  pass 
through  a  tube,  w^hich  has  a  rapid  rotation,  and  which 
twists  it,  in  the  middle,  into  a  cord  of  some  firmness.  It 
is  again  untwisted,  as  fast  as  it  escapes  from  the  tube,  and 
is  wound  upon  the  bobbins,  in  the  form  of  a  dense,  even, 
cord,  but  without  any  twist. 

Spinning. — The  bobbins,  which  contain  the  cotton,  in 
A  state  of  roving,  are  next  transferred  to  the  spinning- 
frame.  It  is  here  once  more  drawn  out  by  rollers,  and 
twisted  by  flyers,  so  that  the  spinning  is  little  more  than 

*  Instead  of  band  c-oi.es,  an  ingenious  mode  of  using  geared  cones, 
now  introduced  in  several  American  factories,  has  already  been  de 
escribed,  page  60. 

t  By  Mr.  Danforth,  of  Massachusetts. 


MULE-SPINNING.  175 

• 

a  repetition  of  the  process  gone  through,  in  making  the 
roving,  except  that  the  cotton  is  now  twisted  into  a  strong 
thread,  and  cannot  any  longer  be  extended,  by  drawing. 
The  flyers  of  the  spinning-frame  are  driven  by  bands, 
which  receive  their  motion,  in  some  cases,  from  a  hori- 
zontal fly-wheel,  and,  in  others,  from  a  longitudinal  cylin- 
der.* As  the  thread  is  sufliciently  strong  not  to  break 
with  a  slight  force,  the  resistance  of  the  bobbins,  by  fric- 
tion, is  rehed  on  to  wind  it  up,  instead  of  having  tlie  spin- 
dles geared  together,  and  turned  with  an  exact  velocity, 
as  they  are  in  the  common  double-speeder.  In  the  spin- 
ning frame,  the  heart-motion  is  retained,  to  regulate  the 
rise  and  fall  of  the  rail  ;  and,  in  those  frames  which  spin 
the  woof,  or  filling,  it  is  applied,  by  a  progressive  sort  of 
cone,  the  section  of  which  is  heart-shaped,  and  which 
acts,  remotely,  to  distribute  the  thread,  in  conical  layers, 
upon  the  bobbins,  that  it  may  unwind  the  more  easily, 
when  placed,  afterwards,  in  the  shuttle. 

Mule  Spinning. — The  processes  of  water-spinning, 
already  described,  are  adequate  to  produce  yarns,  of  suf- 
ficient fineness  for  ordinary  fabrics.  But,  for  producing 
threads  of  the  finest  kind,  another  process  is  necessary, 
which  is  called  stretchings  and  which  is  analogous  to  that 
which  is  performed,  with  carded  cotton,  upon  a  commr^n 
spinniiag-wheel.  In  this  operation,  portions  of  yarn,  sev- 
eral yards  long,  are  forcibly  stretched,  in  the  direction  r^ 
their  length.  It  differs,  therefore,  from  the  operation  €>*' 
drawing,  in  which  a  few  inches,  only,  are  extended  at  • 
time.  The  stretching  is  performed,  with  a  view  to  elop- 
gate  and  reduce  those  places  in  the  yarn,  which  have  ^ 
greater  diameter,  and  are  less  twisted,  than  the  other  parts 
so  that  the  size  and  twist  of  the  thread  may  become  uni- 
form throughout.  To  effect  the  process  of  stretching, 
the  spindles  are  mounted  upon  a  carriage,  which  is  moved, 
back  and  forwards,  across  the  floor  ;  receding,  when  the 
tln-eads  are  to  be  stretched,  and  returning,  when  they  are 
to  be  wound  up.  The  yarn,  produced  by  mule-spinning, 
is  more  perfect  than  any  other,  and  is  employed  in  the 

*  The  latter  method,  which  had  gone  into  disuse,  is  beginnmg  to  be 
revived,  and  to  be  considered  most  advantageous. 
15* 


174  COMBINING  FLEXIBLE   FIBRES. 

m 

fabrication  of  the  finest  artiJes.  The  sewing-thread, 
>pun  by  mules,  is  a  combination  of  two,  four,  or  six,  con- 
stituent threads,  or  phes.  Threads  t>ave  been  produced, 
of  such  fineness,  that  a  pound  of  cotton  has  been  calculat- 
ed to  reach  one  hundred  and  sixty-seven  miles. 

IVarping. — The  first  step,  preparatory  to  weaving,  is 
to  form  a  warp^  which  consists  of  parallel  threads,  con- 
tinued through  the  whole  length  of  the  intended  piece,  and 
sufficient,  in  number,  to  constitute  its  breadth.  It  was, 
formerly,  the  practice  to  attach  the  threads  to  as  many 
pins,  and  to  draw  them  out,  to  the  required  length.  But, 
as  this  method  required  too  much  room,  a  warping  ma- 
chine was  subsequently  used,  in  which  the  mass  of  threads, 
intended  to  constitute  a  warp,  w^as  wound  in  a  spiral  course, 
upon  a  large  revolving  frame,  which  rose  and  fell,  so  as 
to  produce  the  spiral  distribution. 

These  methods  are  now  superseaeu,  n  this  countiy 
by  Moody's  warping-machine,*  an  ingerious  piece  ot 
mechanism,  in  which  a  number  of  bobbins,  eqjal  to  one 
eighth  part  of  the  number  of  threads  in  the  intended  warp, 
are  arranged  upon  the  surface  of  a  con  ".ave  frame.  The 
threads  pass  through  a  reed,  which  separates  the  alternate 
threads,  as  they  are  to  be  kept  in  the  loom  ;  after  which, 
they  are  wound  upon  a  beam,  with  rods  interposed  at  the 
end,  to  preserve  the  separation.  But  the  most  ir4/erest- 
ing  part  of  the  mechanism  is  a  contrivance  for  stopping 
the  machine,  if  a  single  thi^ead  of  the  warp  breaks.  To 
effect  this  object,  a  small  steel  weight,  or  flattened  wire, 
is  suspended,  by  a  hook,  from  each  thread,  so  that  it  falls, 
if  the  thread  is  broken.  Beneath  the  row  of  weights,  a 
cylinder  revolves,  furnished  with  several  projecting  ledges . 
extending  its  whole  length,  parallel  to  the  axis.  Whe. 
one  of  the  w^eights  falls,  by  the  breaking  of  its  thread,  i 
intercepts  one  of  the  ledges,  and  causes  the  cyhnder  to 
exert  its  force  upon  an  elbow,  or  toggle-joint,  which  dis- 
engages a  clucch,  and  stops  the  machine.  After  the  thread 
is  tied,  and  the  weight  raised,  the  machine  proceeds. 

*  Mr.  Paul  Moody,  formerly  of  Walthara,  and  now  of  Lowell,  is  the 
inventor  of  this  machine  ;  likewise  of  the  spinning-frame,  which  winda 
the  woof  in  conical  layers  ;  and  of  great  improvements  in  the  roving 
frame,  the  dressing-frame,  &c. 


DRESSING. WEAVING.  176 

Dressing. — As  the  threads,  which  constitute  the  warp, 
are  Hahle  to  much  friction,  in  the  process  of  weaving,  they 
are  subjected  to  an  operation,  called  dressing,  the  object 
of  which  is,  to  increase  their  strength  and  smoothness,  by 
agglutinating  their  fibres  together.  To  this  end,  they  are 
pressed  between  rollers,  impregnated  with  mucilage,  made 
of  starch,  or  some  gelatinous  material,  and,  immediately 
afterwards,  brought  in  contact  with  brushes,  which  pass 
repeatedly  over  them,  so  as  to  lay  down  the  fibres  in  one 
direction,  and  remove  the  superfluous  mucilage  from  them. 
They  are  then  dried,  by  a  series  of  revolving  fans,  or  by 
steam-cylinders,  and  are  ready  for  the  loom. 

Weaving. — Woven  textures  derive  their  strength  from 
he  same  force  of  lateral  adhesion,  which  retains  the  twis- 
ed  fibres  of  each  thread  in  their  situations.  The  man- 
ner, in  which  these  textures  are  formed,  is  readily  under- 
stood. On  inspecting  a  piece  of  plain  cloth,  it  is  found 
to  consist  of  two  distinct  sets  of  threads,  running  perpen- 
dicularly to  each  other.  Of  these,  the  longitudinal  threads 
constitute  the  warp.,  while  the  transverse  threads  are  called 
the  woof.,  t^^ft,  or  fillings  and  consist  of  a  single  thread, 
passing  backwards  and  forwards.  In  weaving  with  the 
common  loom,  the  warp  is  wound  upon  a  cylindrical  beam, 
or  roller.  From  this,  the  threads  pass  through  a  har- 
ness,- composed  of  movable  parts,  called  the  heddles,  of 
which  there  are  two  or  more,  consisting  of  a  series  of 
vertical  strings,  connected  to  frames,  and  having  loops, 
through  which  the  warp  passes.  When  the  heddles  con- 
sist of  more  than  one  set  of  strings,  the  sets  are  called 
leaves.  Each  of  these  heddles  receives  its  portion  of  the 
alternate  threads  of  the  warp  ;  so  that,  when  they  are 
moved,  reciprocally,  up  and  down,  the  relative  position 
of  the  alternate  threads  of  the  warp  is  reversed.  Each 
time  that  the  warp  is  opened,  by  the  separating  of  its  al- 
ternate threads,  a  shuttle,  containing  the  woof,  is  thrown 
across  it,  and  the  thread  of  a  w^oof  is  immediately  driven 
into  its  place,  by  a  frame,  called  a  lay,  furnished  with  thin 
reeds,  or  wires,  placed  among  the  warp,  like  the  teeth  of 
a  comb.  The  woven  piece,  as  fast  as  it  is  completed,  is 
wound  up  on  a  second  beam,  opposite  to  the  first. 


176 


COMBJNING  FLEXIBLE   FIBRES. 


Power  looms,  driven  by  water,  or  steam,  although  a 
late  invention,  are  now  universally  introduced  into  manu- 
factories of  cotton  and  woollens.  As  the  motions  of  the 
loom  are,  chiefly,  of  a  reciprocating  kind,  they  are  produ- 
ced, in  some  looms,  by  the  agency  of  cranks,  and  in  oth- 
ers, by  cams,  or  wipers,  acting  upon  weights,  or  springs. 

Twilling. — In  the  mode  of  plain  weaving,  last  describ- 
ed, it  will  be  observed,  that  every  thread  of  the  warp 
crosses  at  every  thread  of  the  woof,  and  vice  versa.  In 
articles,  which  are  twilled^  or  'ticeeled^  this  is  not  the  case ; 
for,  in  this  manufacture,  only  the  third,  fourth,  fifth,  sixth, 
&c.,  threads  cross  each  other,  to  form  the  texture.  In 
the  coarsest  kinds,  every  third  thread  is  crossed  ;  but,  in 
finer  fabrics,  the  intervals  are  less  frequent,  and,  in  some 
very  fine  twilled  silks,  the  crossing  does  not  take  place,  till 
the  sixteenth  interval.     In  Fig  178,  is  shown  a  magnified 

Fig.  178. 


section  of  a  piece  of  plain  cloth,  in  which  the  woof  passes, 
alternately,  over  and  under  every  thread  of  the  warp.  In 
Fig.  79,  is  a  piece  of  twilled  cloth,  in  which  the  thread 


Fk.  179. 


r<y: 


ro 


toz 


ro 


of  the  woof  passes,  alternately,  over  four,  and  under  one, 
of  the  threads  of  the  warp,  and  performs  the  reverse,  in 
its  return.  To  produce  this  effect,  a  number  of  leaves 
of  heddles  are  required,  equal  to  the  number  of  threads 
contained  in  the  interval,  between  each  intersection,  in- 
clusive. By  the  separate  movements  of  these,  the  warp 
is  placed  in  the  requisite  positon,  before  each  stroke  of 
the  shuttle.  A  loom,  invented  in  this  country,  by  Mr. 
Batchelder,  of  Lowell,  has  been  applied  to  the  weaving 
-jf  twilled  goods,  by  water-power. 

Twilled  fabrics  are  thicker  than  plain  ones,  when  of  the 
same  fineness,  and  more  flexible,  when  of  the  same  thick- 
ness.    They  are  also  more  suceptible  of  ornamental  va 


DOUBLE-WEAVING. CROSS-WEAVlMr. 


J  77 


riajions.     Jeans,  dimities,  serges,  &c.,are  specimens  of 
this  kind  of  texture. 

Double  Weaving. — In  this  species  of  weaving,  the  fa- 
bric is  composed  of  two  webs,  each  of  which  consists  of 
a  separate  warp,  and  a  separate  woof.  .The  two,  however, 
are  interwoven,  at  intervals,  so  as  to  produce  various  fig- 
ures. The  junction  of  the  two  webs  is  formed,  by  pass- 
ing them,  at  intervals,  through  each  other  ;  so  that  each 
particular  part  of  both  is  sometimes  above,  and  sometimes 
below.  It  follows,  that,  when  different  colors  are  employ- 
ed, as  in  carpeting,  the  figure  is  the  same,  on  both  sides, 
but  the  color  is  reversed.  A  section  of  double  cloth  is 
shown  in  Fig.  180. 

F\2.  180. 


The  weaving  of  double  cloths  is  commonly  performed, 
by  a  complicated  machine,  called  a  draw-loom.,  in  which 
the  w^eaver,  aided  by  an  assistant,  or  by  machinery,  has 
the  command  of  each  particular  thread,  by  its  number. 
He  works  by  a  pattern,  in  which  the  figure  before  him  is 
traced,  in  squares,  agreeably  to  which  the  threads  to  be 
moved  are  selected,  and  raised,  before  each  insertion  of 
the  woof.  Kidderminster  carpets,  and  Marseilles  quilts, 
are  specimens  of  this  mode  of  weaving. 

Cross  Weaving. — This  method  is  used,  to  produce  the 
lightest  fabrics,  such  as  gauze,  netting,  catgut,  &c.  In  the 
kinds  of  weaving  which  have  been  previously  described, 
the  threads  of  the  warp  always  remain  parallel  to  each  oth- 
er, or  without  crossing.  But,  in  gauze-weaving,  the  two 
threads  of  warp,  which  pass  between  the  same  splits  of  the 
reed,  are  crossed  over  each  other,  and  partially  twisted  like 
a  cord,  at  every  stroke  of  the  loom.  They  are,  however, 
twisted  to  the  right  and  left,  alternately,  and  each  shot,  or 
insertion  of  the  woof,  preserves  the  twist  which  the  warp 
has  received.     A  great  variety  of  fanciful  textures  are  pro- 


178  COMBINING  FLEXIBLE  FIBRES. 

duced,  by  variations  of  the  same  general  plan.    Fig.  1.81, 
represents  the  cross-weaving,  used  in  comnaon  gauze. 

Fig.  181. 


Lace.  —  Lace  is  a  complicated,  ornamental,  fabric, 
formed  of  fine  threads  of  linen,  cotton,  or  silk.  It  consists 
of  a  net- work  of  small  meshes,  the  most  common  form 
of  which  is  hexagonal.  In  perfect  thread-lace,  four  sides 
of  the  hexagon  consist  of  threads  which  are  twisted,  while, 
in  the  remaining  two,  they  are  simply  crossed.  Lace  has 
been  commonly  made  upon  a  cushion,  or  pillow,  by  the 
slow  labor  of  artists.  A  piece  of  stiff  parchment  is  stretch- 
ed upon  the  cushion,  having  holes  pricked  through  it,  in 
which  pins  are  inserted-  The  threads,  previously  wound 
upon  small  bobbins,  are  woven  round  the  pins,  and  twist- 
ed, in  various  ways,  by  the  hands,  so  as  to  form  the  requir- 
ed pattern.  The  expensiveness  of  the  different  kinds  of 
lace  is  proportionate  to  the  tediousness  of  the  operation. 
Some  of  the  more  simple  fabrics  are  executed  with  rap- 
idity, while  others,  in  which  the  sides  of  the  meshes  are 
plaited,  as  in  the  Brussels  lace,  and  that  made  at  Valen- 
ciennes, are  difficult,  and  bear  a  much  greater  price. 

The  cheaper  kinds  of  lace  have  long  been  made  by 
machinery  ;  and,  recently,  the  invention  of  Mr.  Heath- 
coat's  lace-machine  has  effected  the  fabrication  of  the 
more  difficult,  or  twisted  lace,  with  precision  and  des 
patch.  This  machine  is  exceedingly  compHcated  and 
ingenious,  and  is  now  in  operation  in  this  country,  and  in 
France,  as  well  as  in  England. 

Carpeting. — Carpets  are  thick  textures,  composed, 
wholly  or  partly,  of  wool,  and  wrought  by  several  dissimi- 
lar methods.  The  simplest  mode  is  that  used  in  weav- 
ing the  Venetian  carpets,  which  is  a  plain  texture,  com- 
Dosed  of  a  striped  woollen  warp,  on  a  thick  woof  of 
linen  thread.  Kidderminster  carpeting  is  composed  by 
two  woollen  webs,  which  intersect  each  other,  in  such  a 
manner,  as  to  produce  definite  figures.      Brussels  carpet 


TAPESTRY. VELVETS.  '  179 

mg  has  a  basis,  composed  of  a  warp  and  woof,  of  strong 
linen  thread.  But,  to  every  two  threads  of  linen,  in  the 
warp,  there  is  added  a  parcel  of  about  ten  threads  of 
woollen,  of  different  colors.  The  linen  thread  never 
appears  on  the  upper  surface  ;  but  parts  of  the  woollen 
threads  are,  from  time  to  time,  drawn  up  in  loops,  so  as 
to  constitute  ornamental  figui^es,  the  proper  color  being, 
e:.ch  time,  selected  from  the  parcel  to  which  it  belongs. 
A  sufficient  number  of  these  loops  is  raised,  to  produce  a 
uniform  surface,  as  seen  in  Fig.  182  ;  and  to  render  them 

Fk.  182. 


equal,  each  row  passes  over  a  wire,  which  is  subsequent- 
ly withdrawn.  In  some  cases,  the  loops  are  cut  through 
with  the  end  of  the  wire,  which  is  sharpened  for  the  pur- 
pose, so  as  to  cut  off  the  threads,  as  it  passes  out.  Ir 
forming  the  figure,  the  weaver  is  guided  by  a  pattern, 
which  is  drawn  in  squares,  upon  a  paper.  Turkey  car- 
pets appear  to  be  fabricated  upon  the  same  general  prin- 
ciples, as  the  Brussels,  except  that  the  texture  is  all  wool- 
len, and  the  loops  larger,  and  always  cut. 

Tapestry. — The  name  of  tapestry  is  given  to  certain 
deUcate  and  complicated  fabrics,  in  which  the  forms  and 
colors  of  natural  objects  are  produced,  with  such  accura- 
cy, as  to  resemble  fine  paintings.  The  mode  of  texture 
used,  to  produce  this  effect,  is,  in  many  respects,  analo 
gous  to  that  by  which  the  finer  carpetings  are  made.  The 
minuteness,  however,  of  the  constituent  parts,  causes  the 
sight  of  the  texture  to  be  lost,  in  the  general  effect  of  the 
piece.  The  fabrication  of  tapestry  is  slow,  intricate,  and 
very  expensive.  The  most  celebrated  manufactory  is  that 
established  by  the  family  of  Gobelins,  and  kept  up  by 
their  successors,  at  Paris. 

Velvets. — The  fine  soft  nap,  by  which  velvet  is  cov- 
ered, is  produced  by  a  method,  not  unhke  that  which  is 
used  in  carpeting  and  tapestry.     It  is  formed  of  a  part 


180  COMBINING  FLEXIBLE   FIBRES. 

of  the  threads  of  the  warp,  which  the  workman  puts,  in 
loops,  on  a  long,  channelled  wire.  Before  the  wire  is 
withdrawn,  the  row  of  loops  is  cut  open,  by  a  sharp  steel 
nistrument  which  is  drawn  along  the  channel  of  the  wire. 
Various  other  fabrics  of  silk,  cotton,  and  wool,  such  as 
thicksets,  plushes,  corduroys,  velveteens,  &c.,  are  cut  in 
a  similar  manner. 

Cotton  counterpanes  are  woven  with  two  shuttles,  one 
containing  a  much  coarser  woof  than  the  other.  The 
coarser  of  the  threads  is  picked  up,  at  intervals,  with  an 
iron  pin,  whtch  is  hooked  at  the  point,  thus  forming  knobs^ 
which  are  made  to  constitute  regular  figures. 

In  cotton  fabrics,  the  web,  when  taken  from  the  loom. 
IS  covered  with  an  irregular  nap,  or  down,  formed  by  the 
projecting  ends  of  the  fibres.  This  is  removed,  in  the 
finest  articles,  by  burning  it  off,  the  heat  being  so  man- 
aged, as  not  to  injure  the  texture  of  the  cloth.  The  oper- 
ation is  performed,  by  drawing  the  web,  very  rapidly,  over 
an  iron  cylinder  which  is  kept  constantly  red  hot,  by  a 
fire  within  it.  The  velocity  of  the  cloth  prevents  it  from 
burning,  while  the  loose  filaments,  which  constitute  the 
nap,  are  singed  off.  The  flame  of  coal-gas  has,  of  late, 
been  applied  to  the  same  purpose. 

Linens. — This  name  belongs  to  fabrics,  which  are  man- 
ufactured from  flax  ;  but  those  made  of  hemp  are  similar 
in  their  properties,  except  in  fineness.  The  length  and 
comparative  rigidity,  of  the  fibres  of  flax,  present  difli- 
culties,  in  the  way  of  spinning  it,  by  the  machinery  which 
is  used  for  cotton  and  wool.  It  cannot  be  prepared,  by 
carding,  as  these  other  substances  are,  and  the  rollers 
are  capable  of  drawing  it  but  very  imperfectly.  The 
subject  of  spinning  flax,  by  machinery,  has  attracted 
much  attention,  and  the  Emperor  Napoleon,  at  one  time, 
oflered  a  reward  of  a  million  of  francs,  to  the  inventor  of 
the  best  machine,  for  this  purpose.  Various  individuals, 
both  in  this  country,  and  in  Europe,  have  succeeded  in 
constructing  machines,  which  spin  coarse  threads  of  linen, 
sufficiently  well,  and  with  great  rapidity.  But  the  manu- 
facture of  fine  threads,  such  as  those  used  for  cambrics 
and  lace,  continues  to  be  performed,  by  hand,  upon  the 
ancient  spinning-wheel. 


WOOLLENS.  181 

Linen  was  manufactured  by  the  Egyptians,  probably, 
one  thousand  five  hundred  years  before  Christ.  Some 
of  it  was  of  exceeding  fineness.  Vast  quantities,  in  the 
form  of  mummy-cloths,  still  remain. 

WOOLLENS. 

The  fibres  of  wool,  being  contorted  and  elastic,  are 
drawn  out  and  spun,  by  machinery,  in  some  respects  sim- 
ilar to  that  used  for  cotton,  but  differing  in  various  partic- 
ulars. Independently  of  the  quality  of  fineness,  there 
are  two  sorts  of  wool,  which  afford  the  basis  of  different 
fabrics,  the  long  wool,  and  the  short.  Long  wool  is  that, 
in  which  the  fibres  are  rendered  parallel,  by  the  process 
of  combing.  It  is  also  known  by  the  name  of  icorstedj 
and  is  the  material,  of  which  camlets,  bombazines,  &c., 
are  made.  Short  wool  is  prepared,  by  carding,  like  cot- 
ton, and  is  used,  in  different  degrees  of  fineness,  for  broad- 
cloths, flannels,  and  a  multitude  of  other  fabrics.  This 
wool,  when  carded,  is  formed  into  small,  cylindrical  rolls, 
which  are  joined  together,  and  stretched,  and  spun,  by  a 
slubbing,  or  roving,  machine,  and  a  jenny,  or  mule  ;  in 
both  of  which,  the  spindles  are  mounted  on  a  carriage, 
which  passes  backwards  and  forwards,  so  as  to  stretch 
the  material,  at  the  same  time  that  it  is  twisted.  On  ac- 
count of  the  roughness  of  the  fibres,  it  is  necessary  to 
cover  them  with  oil,  or  grease,  to  enable  them  to  move 
freely  upon  each  other,  during  the  spinning  and  weaving. 
After  the  cloth  is  woven,  the  oily  matter  is  removed,  by 
scouring,  in  order  to  restore  the  roughness  to  the  fibres, 
preparatory  to  the  subsequent  operation  of  fulling. 

In  articles  which  are  made  of  long  wool,  the  texture 
is  complete,  when  the  stuff  issues  from  the  loom.  The 
pie,ces  are  subsequently  dyed,  and  a  gloss  is  communica- 
ted to  them,  by  pressing  them  between  heated  melalhc 
surfaces.  But,  in  cloths  made  of  short  wool,  the  weav- 
ing cannot  be  said  to  have  completed  the  texture.  When 
the  web  is  taken  from  the  loom,  it  is  too  loose  and  open, 
and,  consequently,  requires  to  be  submitted  to  another  op- 
eration, called  fulling.  This  is  performed  by  a  fulling- 
mill,  in  which  the  cloth  is  immersed  in  water,  and  subject- 
II.  16  XII. 


182  COMBINING  FLEXIBLE   FIBRES. 

ed  to  repeated  compressions,  by  the  action  of  large  beaters, 
formed  of  wood,  which  repeatedly  change  the  position  of 
the  cloth,  and  cause  the  fibres  to  felt,  and  combine  more 
closely  together.  By  this  process,  the  cloth  is  reduced 
in  its  dimensions,  and  the  beauty  and  stability  of  the  tex- 
ture are  greatly  improved.  The  tendency  to  become 
thickened,  by  fulling,  is  peculiar  to  wool  and  hair,  and 
does  not  exist  in  the  fibres  of  cotton,  or  flax.  It  depends 
on  a  certain  r€ughness  of  these  animal  fibres,  which  per- 
nits  motion,  in  one  direction,  while  it  retards  it,  in  anoth- 
er. It  thus  promotes  entanglements  of  the  fibres,  which 
serve  to  shorten  and  thicken  the  woven  fabric.  Before 
the  cloth  is  sent  to  the  fulling-mill,  it  is  necessary  to 
cleanse  it  from  all  the  unctuous  matter,  which  was  ap- 
plied, to  prepare  the  fibres  for  spinning. 

The  nap,  or  downy  surface,  of  broadcloths,  is  raised, 
by  a  process,  which,  while  it  improves  the  beauty,  tends 
somewhat  to  diminish  the  strength,  of  the  texture.  It  is 
produced,  by  carding  the  cloth,  with  a  species  of  burrs, 
the  (ruit  of  the  common  teazle,  {Dipsacus  fullonum^) 
which  is-  cultivated  for  the  purpose.  This  operation  ex- 
tricates a  part  of  the  fibres,  and  lays  them  in  a  parallel 
direction.  The  nap,  composed  of  these  fibres,  is  then 
cut  off,  to  an  even  surface,  by  the  process  of  shearing. 
This  is  performed  in  various  ways  ;  but  in  one  of  the 
most  common  methods,  a  large  spiral  blade  revolves, 
rapidly,  in  contact  with  another  blade,  while  the  cloth  is 
stretched  over  a  bed,  or  support,  just  near  enough  for 
the  projecting  filaments  to  be  cut  off,  at  a  uniform  length, 
while  the  main  textur^^  remains  uninjured. 

FELTING. 

The  texture  of  modern  hats,  which  are  made  of  fur  and 
wool,  depends  upon  the  process  oi felting^  which  is  sim- 
ilar to  that  of  fulling,  already  described.  The  fibres  of 
these  substances  are  rough,  in  one  direction  only  ;  a  cir- 
cumstance which  may  be  perceived,  by  passing  a  hair 
through  the  figures,  in  opposite  directions.  This  rough- 
ness allows  the  fibres  to  glide  among  each  other,  so  that, 
when  the  mass  is  agitated,  the  anterior  extremities  shde 


PAPER-MAKING.  183 

forward,  in  advance  of  the  body,  or  posterior  half  of  the 
hair,  and  serve  to  entangle,  and  contract,  the  whole  mass 
together.  The  materials,  commonly  used  for  hat-making, 
are  the  furs  of  the  beaver,  seal,  rabbit,  and  other  animals, 
and  the  wool  of  sheep.  The  furs  of  most  animals  are 
mixed  with  a  longer  kind  of  thin  hair,  which  is  obliged  to 
be  first  pulled  out,  after  which,  the  fur  is  cut  off,  with  a 
knife.  The  materials  to  be  felted  are  intimately  mixed 
together,  by  the  operation  of  bowings  which  depends  on 
the  vibrations  of  an  elastic  string  ;  the  rapid  alternations 
of  its  motion  being  pecuHarly  well  adapted  to  remove  all 
irregular  knots  and  adhesions,  among  the  fibres,  and  to 
dispose  them  in  a  very  hght  and  uniform  arrangement. 
This  texture,  when  pressed  under  cloths  and  leather, 
readily  unites  into  a  mass  of  some  firmness.  This  mass 
is  dipped  into  a  liquor,  containing  a  little  sulphuric  acid  ; 
and,  when  intended  to  form  a  hat,  it  is  first  moulded  into 
a  large  conical  figure,  and  this  is  afterwards  reduced  in 
its  dimensions,  by  working  it,  for  several  hours,  with  the 
hands.  It  is  then  formed  into  a  flat  surface,  with  several 
concentric  folds,  which  are  still  further  compacted,  in  or- 
der to  make  the  brim,  and  the  circular  part  of  the  crown, 
and  forced  on  a  block,  wiiich  serves  as  a  mould,  for  the 
cylindrical  part.  The  nap,  or  outer  portion  of  the  fur, 
is  raised  with  a  fine  wire  brush,  and  the  hat  is  subsequent- 
ly dyed  and  stiffened,  on  the  inside,  with  glue. 

An  attempt  has  been  made,  and,  at  one  time,  excited 
considerable  expectation  in  England,  to  form  woollen 
cloths  by  the  process  of  felting,  without  spinning  or  weav- 
ing. Perfect  imitations  of  various  cloths,  were  produced  ; 
but  they  were  found  deficient  in  the  firmness  and  dura- 
bihty,  which  belongs  to  woven  fabrics. 

PAPER-MAKING. 

The  combination  of  flexible  fibres,  by  which  paper  is 
produced,  depends  on  the  minute  subdivision  of  the  fibres, 
and  their  subsequent  cohesion.  Linen  and  cotton  rags 
are  the  common  material,  of  which  paper  is  made  ;  but 
hemp,  and  some  other  fibrous  substances,  are  used  for 
the  coarser  kinds.     These  materials,  after  being  washed, 


184  COMBINING   FLEXIBLE   FIBRES 

are  subjected  to  the  action  of  a  revolving  cylinder,  the 
surface  of  which  is  furnished  with  a  number  of  sharp  teeth, 
or  cutters,  which  are  so  placed,  as  to  act  against  other  cut- 
ters, fixed  underneath  the  cylinder.  The  rags  are  kept 
immersed  in  water,  and  continually  exposed  to  the  action 
of  the  cutters,  for  a  number  of  hours,  till  they  are  minute- 
ly divided,  and  reduced  to  a  thin  pulp.  During  this  pro- 
cess, a  quantity  of  chloride  of  lime  is  mixed  with  the 
rags,  the  effect  of  which  is  to  bleach  them,  by  discharging 
the  coloring  matter,  with  which  any  part  of  them  may  be 
dyed,  or  otherwise  impregnated.  Before  the  discovery 
of  this  mode  of  bleaching,  it  was  necessary  to  assort  the 
rags,  and  select  only  those  which  were  white,  to  consti- 
tute white  paper.  If,  however,  the  bleaching  process  be 
carried  too  far,  it  injures  the  texture  of  the  paper,  by  cor- 
roding and  weakening  the  fibres. 

The  pulp,  composed  of  the  fibrous  particles,  mixed  with 
water,  is  transferred  to  a  large  vat,  and  is  ready  to  be  made 
into  paper.  The  workman  is  provided  with  a  mouldy 
whiqh  is  a  square  frame,  with  a  fine  wire  bottom,  resem- 
bling a  sieve,  of  the  size  of  the  intended  sheet.  With 
this  mould,  he  dips  up  a  portion  of  the  thin  pulp,  and  holds 
it  in  a  horizontal  direction.  The  water  runs  out  through 
the  interstices  of  the  wires,  and  leaves  a  coating  of  fibrous 
particles,  in  the  form  of  a  sheet,  upon  the  bottom  of  the 
mould.  The  sheets,  thus  formed,  are  subjected  to  pres- 
sure, first  between  fehs,  or  woollen  cloths,  and  afterwards 
alone.  They  are  then  sized,  by  dipping  them  in  a  thin  so- 
lution of  gelatin,  or  glue,  obtained  from  the  shreds  and  par- 
ings of  animal  skins.  The  use  of  the  size  is  to  increase 
the  strength  of  the  paper,  and,  by  filling  its  interstices, 
to  prevent  the  ink  from  spreading  among  the  fibres,  by 
capillary  attraction.  In  blotting  paper,  the  usual  sizing  is 
omitted. 

The  paper,  after  being  dried,  is  pressed,  examined, 
selected,  and  made  into  quires  and  reams.  Hot-pressed 
paper  is  rendered  glossy,  by  pressing  it  between  hot  plates 
of  polished  metal. 

Paper  is  also  manufactured  by  machinery  ;  and  one 
of  the  most  ingenious  methods  is  that  invented  by  the 


BOOKBINDING.  185 

Messrs.  Fourdrinier.  In  this  arrangement,  instead  oi 
moulds,  the  pulp  is  received  in  a  continual  stream,  upon 
the  surface  of  an  endless  web  of  brass  wire,  which  extends 
round  two  revolving  cylinders,  and  is  kept  in  continual 
motion  forwards,  at  the  same  time  that  it  has  a  tremulous, 
or  vibrating,  motion.  The  pulp  is  thus  made  to  form  a 
long,  continual  sheet,  which  is  wiped  off  from  the  wire 
web,  by  a  revolving  cylinder,  covered  with  flannel,  and, 
after  being  compressed  between  other  cylinders,  is  finally 
wound  into  a  coil,  upon  a  reel,  prepared  for  the  purpose. 

Another  machine  for  making  paper,  consists  of  a  hori- 
zontal revolving  cyhnder  of  wire  web,  which  is  immersed 
in  the  vat,  to  the  depth  of  more  than  half  its  diameter. 
The  water  penetrates  into  this  cylinder,  being  strained 
through  the  wire  web,  at  the  same  time  depositing  a  coat 
of  fibrous  particles  on  the  outside  of  the  cylinder,  w^hich 
constitute  paper.  The  strained  water  flows  oiF,  through 
the  hollow  axis  of  the  cylinder,  and  the  paper  is  wound 
off,  from  the  part  of  the  cylinder  which  is  above  water, 
in  the  form  of  a  continued  sheet. 

As  a  specimen  of  the  rapidity  with  which  paper  may 
now  be  manufactured,  Mr.  Passey,  of  Birmingham,  has 
in  his  possession,  a  document,  the  material  of  which  was 
in  a  state  of  rags,  was  made  into  paper,  dried,  and  printed, 
in  the  space  of  five  minutes,  in  the  presence  of  many 
witnesses. 

Bookbindings  according  to  the  present  mode,  is  per- 
formed in  the  following  manner.  The  sheets  are  first 
folded  into  a  certain  number  of  leaves,  according  to  the 
form  in  which  the  book  is  to  appear  ;  viz.,  two  leaves  for 
fohos,  four  for  quartos,  eight  for  octavos,  twelve  for  duo- 
decimos, &c.  This  is  done  with  a  slip  of  ivory  or  box- 
woodj  called  a  folding-stick.  In  the  arrangement  of  the 
sheets^  the  workmen  are  directed  by  catchwords  or  sig- 
natures, at  the  bottom  of  the  pages.  When  the  leaves 
are  thus  folded,  and  arranged  in  proper  order,  they  are 
usually  beaten  upon  a  stone,  with  a  heavy  hammer,  to 
make  them  solid  and  smooth,  and  are  then  condensed  in 
a  press,  or  by  passing  through  iron  rollers.  After  this 
preparation,  they  are  sewed  in  a  sewing-press,  upon 
16* 


IS6  COMBINING  FLEXIBLE   FIBRES. 

transverse  cords,  or  packthreads,  called  bands,  to  receive 
which,  notches  are  previously  sawed  in  the  back. 

The  number  of  bands  is  usually  six  to  a  folio,  and 
five  for  quartos,  or  any  smaller  size.  The  backs  are 
now  brushed  over  with  glue,  and  the  ends  of  the  bands 
opened,  and  scraped  with  a  knife,  that  they  may  be  more 
conveniently  fixed  to  the  pasteboard  sides  ;  after  which, 
the  back  is  turned  with  a  hammer,  the  book  being  fixed 
in  a  press,  between  boards,  called  backing-boards,  in 
order  to  make  a  groove,  for  admitting  the  pasteboard 
sides. 

When  these  sides  are  applied,  holes  are  made  in  them, 
for  drawing  the  bands  through,  the  superfluous  ends  are 
cut  off,  and  the  parts  are  hammered  smooth.  The  book 
is  next  pressed,  for  cutting,  which  is  done  by  a  particu- 
lar machine,  called  the  plough,  to  which  is  attached  a 
knife.  It  is  put  into  a  press,  called  the  cutting-press, 
betwixt  two  boards,  one  of  which  lies  even  with  the 
press,  for  the  knife  to  run  upon  ;  and  the  other  above, 
for  the  knife  to  cut  against.  After  this,  the  pasteboards 
are  cut  square,  with  a  pair  of  iron  shears  ;  and  the  colors 
are  sprinkled  on  the  edges  of  the  leaves,  with  a  brush, 
made  of  hog's  bristles. 

The  pasteboard  sides  are  now  covered,  by  pasting 
upon  them  leather,  or  whatever  other  material  is  intend- 
ed to  form  the  outside.  The  sprinkling,  or  marbling,  of 
the  covers  is  performed,  with  a  brush  and  a  coloring  li- 
quid. The  covers  are  glazed,  by  applying  to  them  the 
white  of  an  egg,  and  rubbing  them  with  a  heated  steel- 
polisher.  A  thin  piece  of  morocco  is  glued  upon  the 
back,  to  receive  the  lettering,  which  is  impressed  with 
gold-leaf  and  heated  types. 

Cloth  Binding  is  a  recent  improvement,  in  which  a 
piece  of  cloth,  usually  dyed  cotton,  is  embossed  with 
ornamental  figures,  bypassing  it  through  a  roller-press,  be- 
tween engraved  steel  cylinders.  It  is  afterwards  pasted 
upon  the  volume,  in  the  same  manner  as  leather.  Cloth 
binding  is  executed  with  more  despatch,  and  at  less  ex- 
pense, than  that  with  leather. 


ARTS   OF  HOROLOGY.  187 

Works  of  Reference. — Gray's  Treatise  on  Spinning  Machin- 
ery, 8vo.  1819  ; — Duncan's  Essay  on  the  Art  of  Weaving,  Svo. 
1808  ; — Guest's  History  of  the  Cotton  Manufacture,  4to.  1823  ; — 
BoRGNis'  Mechanique  Appliquee  aux  Arts,  1818  ;  torn.  7,  Machines 
a  Confectionner  les  Etoffes ; — Ure,  The  Cotton  Manufacture  of  Great 
Britain,  8vo.  1836  ; — Lardners'  Cabinet  Cyclopedia,  12mo.  vol. 
xxii.  entitled  Silk  Manufacture  ; — Rees'  Cyclopedia,  articles  Cotton 
Manufacture,  Woollen  Manufacture,  &c.  ; — ^Edinburgh  Encyclope- 
dia, articles  Cotton  Spinning,  Cloth  Manufacture,  &c.  Much  of  the 
machinery,  invented  in  this  country,  is  not  described  in  European  works. 


CHAPTER  XIX. 


ARTS     OF    HOROLOGY. 


Sun  Dial,  Clepsydra,  Water  Clock,  Clock  Work,  Maintaining  Power, 
Regulating  Movement,  Pendulum,  Balance,  Scapement,  Descrip- 
tion of  a  Clock,  Striking  Part,  Description  of  a  Watch. 

Horology,  or  the  art  of  measuring  time,  has  received 
the  attention,  and  exercised  the  ingenuity,  of  mankind, 
from  the  earhest  periods.  The  lapse  of  thought,  and  the 
routine  of  ordinary  occupation,  afford  but  imperfect  indi- 
cations of  the  real  passage  of  time  ;  and  the  only  exact 
standard,  by  which  periods  of  duration  can  be  estimated, 
is  that  of  governed  and  regular  motion. 

Sun  Dial. — The  diurnal  movement  of  the  earth,  with 
relation  to  the  heavenly  bodies,  is  the  most  perfect  stand- 
ard of  admeasurement,  for  large  periods  of  time.  It  is 
the  only  one,  by  which  the  brute  creation,  and  the  unciv 
ilized  part  of  mankind,  govern  their  habits  of  life.  This 
motion  has  been  converted  to  practical  use,  for  measuring 
small  periods,  by  the  employment  of  the  sun-dial,  an  in- 
vention, apparently,  of  great  antiquity,  in  which  the  falling 
of  a  shadow,  on  a  surface  opposite  to  the  sun,  indicates 
the  hour  of  the  day.  The  sun-dial  was  known  to  the 
ancient  Egyptians,  Chinese,  and  Bramins,  and  was  used, 
My  the  latter,  for  astronomical  purposes.  It  appears, 
also,  to  have  been  known  to  the  Jews,  in  the  time  of 
Ahaz,  about  seven  hundred  and  forty  years  before  Christ. 


188  ARTS   OF  HOROLOGY. 

The  first  sun-dial  at  Rome  was  set  up  by  Papiriiis  Cur- 
sor, about  three  hundred  years  before  Christ  ;  previously 
to  which  time,  Pliny  tells  us,  there  is  no  mention  of  any 
account  of  time,  but  by  the  sun's  rising  and  setting. 

At  Athens,  there  is  now  standing  an  octagonal  build- 
ing, erected  by  Andronicus  Cyrrhestes,  and  commonly 
called  the  Tower  of  the  Winds.  It  is  shown  in  Fig.  44 
Vol.  I.  Upon  each  of  the  eight  sides  of  this  building, 
is  a  flying  figure,  carved  in  relief,  representing  the  partic 
ula;  wind  which  blew  against  that  side.  Upon  each  side, 
was  also  placed  a  vertical  sun-dial ;  the  gnomon^  or  index, 
which  cast  the  shadow,  projecting  from  the  side,  while  the 
lines,  indicating  the  hour,  were  cut  upon  the  wall.  On  the 
top,  according  to  Vitruvius,  was  the  figure  of  a  Triton, 
which  turned  with  the  wind,  in  the  same  manner  as  a  mod- 
ern weathercock.  The  lines  of  the  dial,  upon  the  wall,  are 
distinctly  extant,  at  the  present  day  ;  and,  although  the 
gnomons  have  disappeared,  the  places  w^here  they  were 
inserted  are  still  visible. 

Clepsydra. — Since  the  sun-dial  could  be  used,  only  in 
the  day  time,  and  in  clear  weather,  a  different  instrument 
was  invented  by  the  ancients,  to  be  used  within  doors,  at 
all  times  ;  and  to  this  was  given  the  name  of  clepsydra. 
The  clepsydra  was  formed  by  a  vessel  of  water,  having  a 
minute  perforation  in  the  bottom,  through  w^hich  the  water 
issued,  drop  by  drop.  It  fell  into  another  vessel,  in  which 
a  light  body  floated,  having  attached  to  it  an  index,  or 
graduated  scale.  As  the  water  increased  in  the  receiv- 
ing vessel,  the  floating  body  rose,  and,  by  its  regularly 
increasing  height,  furnished  an  approximation  to  the  cor- 
rect indication  of  time.* 

The  original  clepsydra  was  but  a  rude  instrument,  and 
must  have  given  imperfect  indications  of  the  true  divisions 
of  time.  When  the  vessel  was  first  filled,  the  drops  must 
have  fallen  faster,  owing  to  the  greater  height  and  pres- 

*  This  instrument  was  invented  in  Egypt,  but  was  brought  into  Rome 
from  Athens.  Pompey,  while  Consul,  introduced  it  into  the  Roman 
Senate  House  ;  and  the  orators  were  obliged  to  limit  the  length  of  their 
speeclies,  by  its  divisions  of  time,  so  that  Pompey  is  designated,  by  one 
of  th\e  historians,  as  the  first  Roman  who  put  bridles  upon  eloquence. 


WATER-CLOCK. CLOCK-WORK.  189 

sure  of  the  fluid  ;  and,  in  proportion  as  it  became  empty, 
the  dropping  would  be  slower,  in  consequence  of  the  di- 
minution of  this  pressure.  The  disadvantage,  however, 
was  remedied,  in  various  ways,  by  the  employment  of 
two  vessels,  one  of  which  was  kept  constantly  full,  by  a 
supply  from  the  other  ;  and  thus  the  water,  being  always 
at  the  same  height,  furnished  its  drops,  under  an  equable 
pressure. 

Water  Clock. — x\n  instrument,  called  a  water-clock, 
was  in  use,  at  a  much  later  date,  and  was  a  subject  of 
extensive  manufacture,  in  some  parts  of  Europe,  a  few 
centuries  ago.  Several  modes  of  constructing  this  instru- 
ment were  devised  ;  but  the  following  is  one  of  the  most 
ingenious.  A  tight,  hollow  cyhnder,  PI.  IV.  Fig.  4,  is 
suspended  by  cords,  wound  round  its  axis,  which  will 
unwind,  as  it  runs  down.  It  has  its  interior  divided  into 
several  compartments,  situated  like  the  buckets  of  a  wa- 
ter-wheel. These  compartments  communicate  with  each 
other,  by  a  minute  aperture,  through  which  water  can 
pass  slowly,  from  one  compartment  to  another.  Before 
the  machine  is  put  in  motion,  a  small  quantity  of  water 
is  introduced  into  the  lower  compartments.  As  the  cyl- 
inder descends,  by  the  unwinding  of  the  cords,  it  is  obliged 
to  revolve  on  its  axis,  until  the  lower  compartments,  which 
contain  the  water,  have  risen  so  far  on  the  ascending  side, 
as  to  produce  an  equilibrium.  It  can  then  unwind  no 
faster  than  the  water  escapes,  from  one  compartment  to 
another,  through  the  minute  apertures.  As  this  requires 
a  considerable  time,  the  cylinder  may  occupy  a  day,  if 
required,  in  descending  from  the  top  to  the  bottom  of  the 
frame,  to  wkich  it  is  attached.  And,  if  the  sides  of  the 
frame  be  marked  with  the  hours  of  the  day,  the  axis  of 
the  cylinder,  as  it  passes  by  them,  will  indicate  the  time 
of  the  day,  with  as  much  accuracy  as  so  imperfect  a 
machine  permits. 

Clock  Work. — In  modern  days,  all  other  methods  of 
measuring  time  have  given  place  to  the  equable  motion, 
produced  by  the  action  of  machinery  on  the  pendulum 
and  balance.  Timekeepers,  constructed  on  this  princi- 
ple, began  to  be  known  in  Europe,  about  the  fourteenth 


190  ARTS   OF  HOROLOGY. 

century,  but  were  formed  in  a  rude  and  imperfect  man 
ner,  until  the  middle  of  the  seventeenth.  Since  that  pe- 
riod, the  learning  of  philosophers,  and  the  ingenuity  of 
artists,  have  been  extensively  applied  to  their  improve- 
ment *>  and  few  subjects,  connected  with  the  mechanic 
arts,  have  called  forth  more  inventive  c.cuteness,  elabor- 
ate experiment,  and  exact  calculation. 

Before  proceeding  to  a  description  of  the  entire  me- 
chanism of  a  clock,  or  watch,  it  will  be  useful  to  attend 
to  some  of  the  general  principles,  and  essential  parts,  of 
a  timekeeper.  These  will  be  most  easily  made  intelligi- 
ble, by  directing  the  attention  to  the  following  subjects. 
1.  The  maintaining  power.  2.  The  regulating  move- 
ment.    3.   The  method  of  connection. 

Maintaining  Power. — The  force,  which  is  employed 
to  sustain  the  motions  of  timekeepers,  does  not  require  to 
be  of  a  pow^erful  kind.  It  must,  however,  be  steady  and 
uniform,  in  its  action.  Gravity  and  elasticity,  applied 
through  the  medium  of  weights  and  springs,  are  the  only 
means  now  employed,  to  communicate  motion  to  these 
machines.  In  clocks,  the  maintaining  force  is  usually 
derived  from  a  iceight.  A  weight  acts  with  perfect  uni- 
formity, from  the  beginning  to  the  end  of  its  descent,  pro- 
vided the  line,  which  suspends  it,  is  of  equal  size  through- 
out, and  that  this  line  is  w^ound  upon  a  true  and  perfect 
cylinder.  In  portable  timekeepers,  the  weight,  for  ob- 
vious reasons,  cannot  be  employed  ;  and  the  springs  al- 
though a  less  perfect  and  equable  power,  is  obliged  to 
be  substituted.  From  the  oldest  clocks  which  remain,  it 
appears,  that  the  spring  was  in  use  before  the  weight ;  and 
one  of  the  first,  ever  made,  is  still  preserved  at  Brussels, 
in  which  the  spring  is  an  old  sword-blade,  from  which  a 
piece  of  catgut  is  wound  upon  the  cylinder  of  the  first 
wheel.  The  principal  difficulty  in  the  use  of  the  spring 
is,  that  its  action  is  unequal,  and  that  the  more  it  is  bent, 
the  greater  force  it  exerts,  to  return  to  its  natural  situa- 
tion. The  spring  of  a  watch,  as  it  is  now  used,  is  a 
long  plate  of  steel,  coiled  up  into  a  spiral  form.  From  the 
outside  of  this,  proceeds  a  chain,  which  is  attached,  not  to 
a  cylinder,   as  is  done"   willi   ihc  weight,   but  to  a  spiral 


REGULATING  MOVEMENT. PENDULUM.     191 

roller,  called  a  fusee,  which,  by  its  conical  form,  gives- to 
the  spring  an  increased  mechanical  advantage,  in  propor- 
tion as  its  power  diminishes.  The  fusee  has  already  been 
described,  on  page  62. 

In  some  of  the  watches  which  are  now  made,  the  fusee 
and  the  chain  are  dispensed  with.  The  barrel,  which 
incloses  the  spring,  has  a  toothed  circle  on  its  outside, 
which  turns  round,  as  the  spring  unwinds,  and  gives  mo- 
tion t:>  the  machinery.  But,  in  this  case,  the  spring  is 
made  larger  than  common,  and  only  the  middle  part  of 
its  action  is  used,  it  being  never  wound  up  so  far,  as  to 
call  forth  its  greatest  strength,  nor  suffered  to  run  down, 
so  far  as  to  be  materially  weakened. 

Regulating  Movement. — In  the  mechanism  of  clocks 
and  watches,  it  is  necessary,  so  far  to  retard  the  move- 
ment of  the  maintaining  force,  i.  e.,  of  the  weight  or 
spring,  that  it  may  be  hours  and  days  in  expending  itself, 
and  that  the  timekeeper  may  require  to  be  wound  up,  only 
at  distant  and  convenient  periods.  This  is,  in  part,  ef- 
fected, by  the  successive  combination  of  wheels  and  pin- 
ions, the  last  of  which  turns  round  many  hundred  times, 
while  the  first  turns  round  once.  But,  if  a  timekeeper 
possessed  only  wheels  and  pinions,  it  would  run  down, 
with  a  rapidly  accelerated  motion,  in  the  course  of  a  few 
seconds.  It  becomes,  therefore,  necessary,  to  connect 
with  it  another  motion,  which  cannot  be  accelerated,  be- 
yond a  certain  degree,  by  any  given  force.  This  mo 
tion  is  obtained,  in  clocks,  from  the  pendulum^  and,  in 
watches,  from  the  balance  ;  and  it  is  the  one  which  it 
was  proposed  to  consider,  as  the  second  head,  under  the 
name  of  the  regulating  movement. 

Pendulum. — A  pendulum  is  a  weight,  capable  of  vi- 
brating about  a  point,  from  which  it  is  suspended.  If  the 
curve,  in  which  the  pendulum  moves,  be  a  circular  arc, 
it  is  necessary,  that  the  length  of  the  vibrations  should  be 
exactly  equal  ;  otherwise,  the  pendulum  will  not  keep  true 
time.  But,  if  the  curve  be  a  cycloidal  one,  the  pendulum 
will  move,  back  and  forward,  in  equal  times,  whatever  be 
the  length  of  its  vibrations.  In  practice,  it  is  found  diffi- 
cult to  make  a  pendulum  move  in  a  cycloidal  path,  with- 


l92  ARTS    OF   HOROLOGY. 

out  too  much  friction.  It  is,  therefore,  customary,  ni 
clocks,  to  use  pendulums,  moving  in  circular  arcs,  these 
arcs  being  made  to  approximate  to  cycloids,  by  being  as 
short  as  possible. 

Pendulums,  when  set  in  mot'on,  would  continue  to  vi- 
brate forever,  were  it  not  for  the  retarding  effect  of  fric- 
tion, and  the  resistance  of  the  atmosphere.  The  former 
of  these  is  partly  obviated,  by  hanging  the  pendulum  upon 
a  thin  spring,  and  the  latter,  by  forming  it  with  a  sharp 
edge.  Still,  a  considerable  force  is  requisite  to  sustain 
the  motion,  and  this  force,  in  clocks,  is  derived  from  the 
weight. 

That  pendulums  may  vibrate  in  equal  periods,  and  thus 
furnish  a  correct  measure  of  time,  it  is  necessary,  that 
they  should  always  be  of  uniform  length  ;  for  pendulums 
of  different  lengths  differ  in  their  vibrations,  as  the  square 
roots  of  their  lengths.  Now,  such  is  the  effect  of  heat, 
in  expanding  all  known  substances,  particularly  metals, 
that  the  same  pendulum  is  always  longer  in  summer  than 
it  is  in  winter,  and  sufficiently  so,  to  affect  the  correctness 
of  the  timepiece,  to  which  it  is  attached.  To  remedy  this 
difficulty,  various  ingenious  contrivances  have  been  resort- 
ed to,  the  most  common  of  which  are,  combinations  of 
metals,  so  connected,  as  to  expand  in  opposite  directions, 
counterbalancing  each  other,  so  as  to  keep  the  centre  oi 
oscillation  in  one  place.  This  is  sometimes  effected,  in 
the  gridiron  pendulum,  by  combining  bars,  or  rods,  of 
steel  and  brass  ;  and,  in  the  mercurial  pendulum,  by  en- 
closing a  quantity  of  quicksilver,  in  a  tube,  near  the  bot- 
tom of  the  pendulum. 

Balance — As  the  pendulum  depends  upon  the  force  of 
gravity,  for  its  motions,  it  obviously  cannot  be  employed 
for  watches,  or  portable  timekeepers,  which  are  liable  to 
change  their  position.  A  substitute  is  found  in  the  bal- 
ance^ which  is  commonly  a  wheel,  moving  on  an  axis, 
and  which,  when  thrown,  backward  and  forward,  by  oppo- 
site appHcations  of  the  moving  force,  performs  its  vibra- 
tions in  equal  times.  The  balance  is  liable  to  the  same 
irregularities,  from  expansion  and  contraction,  as  the  pen- 
dulum, and  is  corrected  in  a  similar  manner  ;  and  watches 


SCAPEMENT.  i93 

go  best,  when  they  are  kept  in  the  uniform  heat  of  the 
body. 

The  quantity  of  matter,  accumulated  in  the  balance- 
wheel  of  a  common  watch,  is  so  extremely  small,  that  it 
seems  impossible,  that  it  should  exert  a  perfect  regula- 
ting power.  The  want  of  weight,  however,  is,  in  some 
measure,  made  up,  by  causing  it  to  perform  large  vibra- 
tions, and  to  move  with  great  velocity.  The  rim  of 
the  balance-wheel,  in  a  good  watch,  frequently  moves 
through  ten  inches  in  every  second.  This  velocity  is 
produced  by  the  hair-spring,  which  throws  the  balance 
back  to  the  point  of  equilibrium,  as  fast  as  it  is  thrown 
out,  in  either  direction,  by  the  moving  force ;  thus  per- 
forming for  the  balance,  what  gravity  does  for  the  pen- 
dulum. If  the  hair-spring  be  taken  away,  a  watch  will 
lose  more  than  twelve  hours  in  twenty-four,  and  go  much 
more  irregularly.  The  operation  of  the  common  regula- 
tor of  a  watch  is,  to  tighten,  or  relax,  this  hair-spring,  by 
making  its  effective  part  longer  or  shorter,  thus  accelera- 
ting, or  retarding,  the  speed  of  the  balance. 

Scapement. — It  remains  to  consider  the  third  part,  or 
scapement,  by  which  the  rotary  motion  of  the  wheels  is 
converted  into  the  reciprocating  one  of  the  pendulum  and 
balance.  In  the  scapement,  a  certain  part,  connected 
with  the  pendulum,  or  balance,  is  put  in  the  way  of  the 
last,  or  most  rapid,  wheel,  so  that  only  one  tooth  of  this 
wheel  can  escape  by  it,  during  each  vibration.  Thus,  the 
pendulum,  or  balance,  while  it  receives  its  motion  from 
this  wheel,  becomes,  in  its  turn,  the  regulator  of  its  velo 
city. 

The  crutch,  or  anchor-scapement,  used  in  clocks, 
and  the  common  pailet-scapement  with  a  contrate-wheel, 
which  is  the  kind  most  extensively  used  in  watches,  have 
been  already  explained,  under  the  head  of  Machinery, 
page  72.  The  horizontal  scapement.  Fig.  183,  con- 
sists of  a  wheel,  A,  with  elevated  teeth,  the  outer  surface 
of  which  is  curved  obliquely.  These  teeth  act  upon  the 
edges  of  a  hollow  half  cylinder,  C,  the  axis  of  which  is 
parallel  to  that  of  the  wheel,  and  carries  the  balance  upon 
one  of  its  extremities.  When  a  tooth  of  the  scape-wheel 
11=  17  xn. 


194  ARTS   OF  HOROLOGY. 

Fig.  183 


Strikes  the  first  edge  of  the  cylinder,  it  causes  it  to  re- 
cede, moving  the  balance  in  one  direction.  The  tooth 
then  enters  the  hollow  part  of  the  cylinder,  and  strikes 
upon  the  opposite  side.  Before  it  can  escape,  the  cylin 
der  is  obliged  to  turn  in  the  opposite  direction,  and  thus 
a  vibrating  movement  is  kept  up,  in  the  cylinder  and  bal- 
ance. 

A  multitude  of  other  scapements  have  also  been  in 
troduced,  by  different  artists,  varying  from  each  other,  in 
the  complication  of  their  structure,  and  accuracy  of  their 
movements.  But  these  must,  necessarily,  be  omitted. 
The  operation  of  the  simpler  forms,  already  described, 
will  be  more  intelligible,  taken  in  connexion  with  the 
wheel-work,  next  to  be  noticed. 

Description  of  a  Clock. — In  PI.  IV.  several  views  are 
given  of  the  mechanism  of  a  clock,  consisting  of  the  go- 
ing part^  which  moves  constantly,  and  carries  the  hands ; 
and  the  striking  part.,  which  announces  the  hour.  Fig. 
1,  PI.  IV.  is  an  elevation  of  the  clock,  with  the  wheels 
seen  edgewise,  showing  the  going  part ;  the  striking 
movements  being  omitted,  in  this  figure,  to  avoid  confu- 
sion. Fig.  2,  is  a  front  view  of  the  wheel-work  of  both 
going  and  striking  parts  ;  and  Fig.  3,  is  the  dial-work.,  or 
mechanism,  immediately  under  the  dial,  or  face  of  the 
clock,  and  is  that  part  which  puts  the  striking  train  in  mo- 
tion, every  hour.  A  clock  of  this  kind  contains  two  in- 
dependent trains  of  wheel-work,  each  with  its  separate 
first  mover.  One  is  constantly  going,  to  indicate  time,  by 
the  hands  on  the  dial-plate ;  the  other  is  put  in  motion, 
once  in  an  hour,  and  strikes  a  bell,  to  tell  the  hour  at  a 
distance.      The  part,  marked    [a,]  in  Figs.  1  and  2,  is 


DESCRIPTION  OF  A  CLOCK.  195 

the  barrel  of  the  going  part ;  it  has  a  catgut  band,  [6,] 
wound  round  it,  suspending  the  weight,  which  keeps  the 
clock  in  motion.  The  part,  marked  96,  is  a  wheel,  call- 
ed the  first,  or  great  "u'lieel,  of  ninety-six  teeth  upon  the 
end  of  a  barrel,  turning  a  pinion,  8,  of  eight  leaves,  on 
an  arbor,*  which  carries  the  minute-hand  ;  also,  64,  is 
a  wheel  of  sixty-four  teeth,  on  the  same  arbor,  called  the 
centre-wheel,  turning  the  wheel,  60,  by  a  pinion  of  eight 
leaves  on  its  arbor.  This  last  wheel  gives  motion  to  the 
pinion  of  eight,  on  the  arbor  of  the  swing-wheel,  30, 
which  has  thirty  teeth.  The  parts  [c?/i]  are  the  pallets 
of  the  scapement,  fixed  on  an  arbor,  [e,]  Fig.  1,  going 
through  the  back  plate  of  the  clock's  frame,  and  carrying 
a  long  lever,  [/.]  This  lever  has  a  small  pin,  projecting 
from  its  lower  end,  going  into  an  oblong  hole,  made  in 
the  rod,  B,  of  the  pendulum. 

The  pendulum  consists  of  an  inflexible  metalhc  rod,  sus 
pended  by  a  very  slender  piece  of  steel  spring,  D,  from 
a  brass  bar,  E,  screwed  to  the  frame  of  the  clock,  having 
a  weight  at  its  lower  end,  not  seen  in  the  figure ;  in  the 
present  case,  thirty-nine  and  one  eighth  inches  from  the 
suspension,  D.  When  this  pendulum  is  moved  from  the 
perpendicular  line,  in  either  direction,  and  suffered  to  fall 
back  again,  it  swings  nearly  as  much  beyond  the  perpen- 
dicular, on  the  contrary  side,  and  then  returns.  This  it 
will  continue  to  do,  for  some  time  ;  and  each  of  these  vi- 
brations will  be  performed  in  one  second  of  time,  when 
the  pendulum  is  of  the  above  length.  This  is  the  meas- 
urer of  the  time  ;  and  the  office  of  the  clock  is  only  to  in- 
dicate the  number  of  vibrations  it  has  made,  and  to  give 
it  a  small  impulse,  each  time,  to  keep  it  going,  as  the  re- 
sistance of  the  air,  and  elasticity  of  the  spring,  D,  would 
otherwise,  in  a  short  time,  cause  it  to  stop.  By  the  ac- 
tion of  the  weight,  appHed  to  the  cord,  [6,]  which  is  called 
the  maintaining  power,  the  wheels  are  all  turned  round ; 

*  The  terms  arbor,  shaft,  axle,  and  axis,  are  synonymously  used  by 
mechanics,  to  express  the  bar,  or  rod,  which  passes  through  the  centre 
of  a  wheel.  The  terminations  of  a  horizontal  arbor  are  called  gud- 
geons, and  of  an  upright  one,  frequently,  pivots.  The  term  axis,  in 
a  more  exact  sense,  may  mean  merely  the  longest  central  diameter,  or 
a  diameter  about  which  motion  takes  place. 


I9b  ARTS   OF   HOROLOGY. 

and  if  the  pallets  [c?  and  h]  were  removed,  the  swing- 
wheel,  30,  would  revolve,  with  great  velocity,  in  the  direc- 
tion from  30  to  [f/,]  until  the  weight  reached  the  ground. 
The  teeth  of  these  pallets  are  so  placed,  that  one  of  them 
always  engages  the  wheel,  and  prevents  it  from  turning 
more  than  half  a  tooth  at  a  time.  In  the  figure,  the  pallet 
[d]  has  the  nearest  tooth  of  the  w^heel  resting  on  it,  and 
the  pendulum  is  on  the  side  [/i]  of  the  perpendicular. 
When  it  returns,  it  moves  the  pallet,  [c/,]  so  as  to  allow  the 
tooth  of  the  wheel  to  slip  off;  but,  in  the  mean  time,  the 
pallet  [/i]  has  interposed  its  point,  in  the  way  of  the  tooth 
next  it,  and  stops  the  wheel,  till  the  next  vibration,  or 
second.  The  distance  between  the  two  pallets  [d  and 
/i]  is  so  adjusted,  that  only  half  a  tooth  of  the  wheel 
escapes,  at  each  vibration ;  and,  as  the  wheel  has  thirty 
teeth,  it  will  revolve  once  in  sixty  vibrations,  of  one  second 
each,  or  in  one  minute  ;  consequently,  a  hand,  on  the  arbor 
of  this  wheel,  will  indicate  seconds,  on  the  dial-plate,  F, 
which  is  a  circle,  divided  into  sixty.  The  pinion  of  eight, 
on  its  arbor,  is  turned  by  a  wheel  of  sixty,  which,  conse- 
quently, will  turn  once  in  seven  turns  and  a  half  of  the 
other,  or  in  seven  minutes  and  thirty  seconds,  or,  in  one 
eighth  of  an  hour.  Its  pinion  of  eight  is  moved  by  a  wheel 
of  sixty-four,  or  eight  times  itself,  which  will  turn  in  one 
eighth  part  of  the  time.  This  will  be  an  hour  ;  and,  there- 
fore, the  arbor  of  this  wheel  carries  the  minute-hand  of 
the  clock.  The  great  wlieel  of  96,  being  twelve  times  the 
number  of  the  pinion  eight,  will  turn  once  in  twelve  hours, 
and  the  barrel,  [a,]  with  it.  The  cord  of  catgut  goes 
round  sixteen  times,  so  that  the  clock  w^ill  go  eight  days. 
The  hour-hand  of  the  clock  is  turned  by  the  wheel- 
work,  shown  in  Figs.  1  and  3.  On  the  end  of  the  arbor 
of  the  centre  wheel,  64,  a  tube  is  fitted,  so  as  to  go  round 
with  it,  by  friction.  This  carries  the  minute-hand  ;  and, 
if  the  clock  should  require  correction,  the  hand  may  be 
slipped  round,  without  moving  the  wheels.  This  tube 
has  a  pinion  of  forty  teeth  on  its  lower  end,  indicated  by 
a  dotted  circle.  This  turns  another  wheel,  40,  of  forty 
teeth,  which  has  a  pinion  of  six  teeth  on  its  arbor,  turning 
a  wheel,  72,  of  seventy-two  teeth.     The  two  wheels,  40, 


STRIKING  PART.  197 

will  both  turn  in  an  hour ;  and  72,  in  twelve  hours.  The 
arbor  of  this  wheel  has  the  hour-hand,  and  is  a  tube,  going 
over  the  arbor  of  the  minute-hand,  so  that  the  two  hands 
are  concentric.  The  barrel  [a]  is  fitted  to  an  arbor,  com- 
ing through  the  plate  of  the  clock,  and  filed  square,  to  put 
on  a  key,  to  wind  up  the  weight.  The  great  wheel,  96, 
is  not  fixed  fast  to  the  arbor,  but  has  a  click  on  it,  which 
takes  the  teeth  of  a  ratchet-wheel,  cut  on  the  barrel ;  so 
that  the  barrel  may  be  turned  in  one  direction,  to  wind  up 
the  weight,  without  the  wheel ;  but,  by  the  descent  of  the 
weight,  the  wheels  will  be  turned  with  the  barrel,  by  the 
click. 

Striking  Part. — Having  now  considered  the  going  part 
of  the  clock,  it  remains  to  dfscribe  the  mechanism  by 
which  the  hour  is  struck.  In  Fig.  2,  78,  is  a  great  wheel 
of  seventy-eight  teeth,  provided  with  a  barrel  and  chck, 
as  in  96  ;  it  turns  a  pinion  of  eight.  On  the  same  arbor 
is  a  wheel,  64,  turning  a  pinion  of  eight,  on  the  arbor  of 
the  wheel  [o]  of  forty-eight.  This  turns  another  pinion 
of  eight,  and  w-heel  [j)]  of  forty-eight,  which  turns  a  pin- 
ion of  six,  on  the  sam.e  arbor,  with  a  thin  vane  of  metal, 
seen  edgewise,  which  is  called  the  fly,  and  which,  by  the 
resistance  of  the  air  to  its  motion,  regulates  the  velocity 
of  the  wheels. 

The  wheel,  64,  has  eight  pins  projecting  from  it,  which 
raise  the  tail  [n]  of  the  hammer,  as  they  revolve.  The 
hammer  is  returned,  violently,  when  the  pins  leave  its  tail, 
by  a  spring;  [?7i,]  pressing  on  the  end  of  a  pin,  put  through 
ts  arbor,  and  strikes  the  bell.  The  hammer  and  bell  are 
behind  the  plate,  and,  therefore,  unseen.  There  is  a  short 
spring,  [/,]  which  the  other  end  of  the  pin  through  the  ar- 
bor touches,  just  before  the  hammer  strikes  the  bell.  Its 
use  is,  to  lift  the  hammer  off  the  bell,  the  instant  it  has 
struck,  that  it  may  not  stop  the  sound.  The  pins  in  the 
wheel,  64,  must  pass  by  the  hammer-tail  seventy-eight 
times,  in  striking  the  twelve  hours,  l-f2-t-3+4-f-5-|-6+ 
7+8+9+10+11+12=78  ;  and,  as  its  pinion  has  eight 
leaves,  each  leaf  of  the  pinion  answers  to  a  pin  in  the 
wheel,  64.  Now,  as  the  great  wheel  has  seventy-eight 
teeth,  it  will  turn  once  in  twelve  hours,  the  same  as  the 
17* 


108  ARTS   OF  HOROLOGY. 

Other  great  wheel,  96.  In  the  wheel,  64,  eight  of  its  teeth 
correspond  to  one  of  the  pins  of  the  hammer,  and,  as  the 
pinion  of  the  wheel  [oj  has  eight  teeth,  it  (wheel  o)  will  turn 
once,  for  each  stroke  of  the  hammer.  By  the  remaining 
wheels,  one,  [o,]  multiplying  six  times,  and  the  other,  [p, ] 
eight  times,  the  fly  will  turn  6X8=48  times,  for  one  turn 
of  [o,]  which  answers  to  one  stroke  of  the  hammer. 

Fig.  3,  is  also  mechanism,  relating  to  the  striking  part. 
Behind  [r,]  there  is  a  small  pinion,  of  one  tooth,  called  the 
gathering-pallet  J  on  the  arbor  of  the  wheel,  [o,]  which, 
consequently,  turns  once,  for  each  stroke  of  the  hammer. 
The  part,  marked  [Sra;,]  is  a  portion  of  a  large  wheel, 
and  is  called  the  rack.  The  part  [t]  is  an  arm  attached 
to  the  rack,  whose  end  r«sts  against  a  spiral  plate,  V, 
called  the  snail,  which  is  fixed  on  the  tubular  arbor,  be- 
fore described,  of  the  hour-hand  and  wheel,  72,  and  turns 
round  with  it  once  in  twelve  hours.  The  snail  is  divided 
into  twelve  equal  angles,  of  thirty  degrees  each,  and,  as 
it  turns,  each  of  these  answers  to  an  hour.  The  circular 
arcs,  forming  the  circumference  of  the  snail,  are  struck 
from  the  centre  of  the  arbor,  between  each  division,  with  a 
different  radius,'  decreasing  a  certain  quantity,  each  time, 
in  the  order  of  the  hours.  The  circular  part  of  the  rack, 
14,  is  cut  intx)  teeth,  each  of  which  is  of  such  a  length, 
that  every  step  upon  the  snail  shall  answer  to  one  of  them. 
At  [^0,]  is  a  spring,  pressing  against  the  tail  of  the  rack,  and 
acting  to  throw  the  arm  of  the  rack  against  the  snail.  The 
part  Ig]  is  a  click,  called  the  hawk's-bill,  taking  into  the 
teeth  of  the  rack,  and  holding  it  up,  in  opposition  to  the 
spring,  [io.~\  The  part  [ik']  is  a  three-armed  detent, 
called  the  warning-piece.  The  arm  [/c]  is  bent  at  its 
end,  and  passes  through  a  hole,  in  the  front  plate  of  the 
clock,  so  as  to  catch  a  pin,  placed  in  one  of  the  arms  of 
the  wheel,  [p,]  Fig.  2,  and  which  describes  the  dotted 
circle,  in  Fig.  3.  The  other  arm  [i~\  stands,  so  as  to 
fall  in  the  way  of  a  pin,  in  the  wheel,  40.  In  the  pre- 
sent position  of  the  figure,  the  wheels  of  the  striking  train 
are  in  motion,  and  would  continue  turning,  until  the  gath- 
ering-pallet at  \r]  which  turns  once,  at  each  stroke  of 
the  hammer,  by  its  tooth  lifts  the  rack,  [s,]  in  opposition 


STRIKING  PART.  199 

to  ihe  spring,  [tc,]  one  tooth,  each  turn  ;  and  the  hawk's- 
bill  [g]  retains  the  rack,  until  a  pin,  in  the  end  of  the 
rack,  is  brought  in  the  way  of  the  lever  of  the  gathering- 
pallet,  [r,]  and  stops  the  wheels  from  turning  any  further. 
It  is  in  this  position,  with  the  rack  wound  up,  till  its  pin 
arrests  the  tail,  [r,]  that  we  shall  begin  to  describe  the 
operation  of  the  striking  of  the  clock. 

The  wheel,  40,  as  has  been  said  before,  turns'once  in 
an  hour  ;  and,  consequently,  at  the  expiration  of  every 
hour,  the  pin  in  it  takes  the  end,  [i,]  and  moves  it  to- 
wards the  spring  near  it.  This  depresses  the  end,  [/c,] 
until  it  falls  in  the  circle  of  the  motion  of  the  pin,  in  the 
wheel,  [p,]  Fig.  2.  At  the  same  time,  the  short  tail  de- 
presses one  end  of  the  hawk's-bill,  and  raises  the  other, 
[^,]  so  as  to  clear  the  teeth  of  the  rack,  [5.]  Immedi- 
diately,  the  spring  [10]  throws  the  rack  back,  until  the 
end  of  its  tail  [f]  touches  that  part  of  the  snail  which  is 
nearest  it.  When  the  rack  falls  back,  the  pin  in  it  is 
mov^d  clear  of  the  gathering-pallet,  [r,]  and  the  wheels 
are  set  at  hberty.  The  maintaining  power  puts  them  in 
motion  ;  but,  in  a  very  short  time,  before  the  hammer  has 
struck,  the  pin  in  the  wheel  [p]  falls  against  the  end  of 
[fc,]  and  stops  the  whole.  This  operation  happens,  a 
few  minutes  before  the  clock  strikes,  and  this  noise  of  the 
wheels  turning  is  called  the  warning.  When  the  hour  is 
expired,  the  wheel,  40,  has  turned  so  far,  as  to  allow  the 
end  of  [i]  to  slip  over  its  pin,  as  in  the  figure.  The  small 
spring,  pressing  against  it,  raises  the  end,  [/c,]  so  as  to 
be  within  the  circle  of  the  pin,  in  the  wheel,  [p,]  Fig.  2. 
Every  obstacle  is  now  removed,  and  the  w^heels  run  on 
the  pinion  ;  the  wheel,  64,  raises  the  hammer,  [r,]  and 
it  strikes  on  the  bell  ;  the  gathering-pallet  [r]  takes  up 
the  rack,  one  tooth  at  each  turn,  the  hawk's-bill  [g]  re- 
taining it,  until  the  pin  [x]  in  the  rack,  comes  under  the 
gathering-pallet,  [r,]  and  stops  the  motion  of  the  whole 
machine,  till  the  pin  in  the  wheel,  40,  at  the  next  hour, 
takes  the  warning  piece,  [i/c,]  and  repeats  the  operation 
we  have  now  described.  As  the  gathering-pallet  turns 
once,  for  each  blow  of  the  hammer,  and  its  tooth  gathers 
up  one  tooth  of  the  rack,  at  each  turn,  it  is  evident,  that 


200  ARTS  OF  HOROLOGY. 

the  number  of  teeth,  which  the  rack  is  allowed  to  fall 
back,  hmits  the  number  ot  strokes  the  hammer  will  rauke. 
This  is  done  by  the  rack's  tail,  [f,]  resting  on  the  snail. 
Each  step  of  the  snail  answers  to  one  tooth  of  the  rack, 
and  one  stroke  of  the  hammer.  At  each  hour,  a  fresh 
step  of  the  snail  is  turned  to  the  tail  of  the  rack,  and,  by 
tliis  means,  the  number  of  strokes  is  made  to  increase  one, 
at  each  time,  from  one  to  twelve. 

Description  of  a  Watch. — In  PI.  V.,  several  views 
are  given  of  the  construction  of  a  common  portable  watch. 
Fig.  1,  represents  the  wheel-work,  immediately  beneath 
the  dial-plate,  and  also  its  hands,  the  circles  of  hours  and 
minutes  being  marked,  though  the  dial,  on  which  these  are 
engraved,  is  removed.  Fig.  2,  is  a  plan  of  the  wheel- 
work,  all  exhibited  at  one  view,  for  which  purpose,  the 
upper  plate  of  the  watch  is  removed.  Fig.  3,  is  a  plan 
of  the  balance,  and  the  work  situated  upon  the  upper  plate. 
Fig.  4,  shows  the  great  wheel,  and  the  pottance-wheel, 
detached.  Fig.  5,  the  spring-barrel,  chain,  and  fusee, 
detached  ;  and  Fig.  6,  is  an  elevation  of  all  the  move- 
ments together,  the  works  being  supposed  to  be  opened 
out  into  a  straight  line,  to  exhibit  them  all  at  once.  Fig. 
7,  is  a  detached  view  of  the  balance,  together  with  the 
scapement,  in  action. 

The  principal  frame,  for  supporting  the  acting  parts  of 
the  watch,  consists  of  two  circular  plates,  marked  C  and 
D,  in  the  figures.  Of  these,  the  former  is  called  the 
upper  plate,  and  the  latter,  the  pillar-plate,  from  the  cir- 
cumstance that  the  four  pillars,  EE,  which  unite  the  two 
plates,  and  keep  them  a  proper  distance  asunder,  are  fas- 
tened firmly  into  the  lower  plate  ;  while  the  other  ends 
pass  through  holes,  in  the  upper  plate,  C,  and  have  small 
pins  put  through  the  ends  of  the  pillars,  to  keep  the  whole 
together.  By  drawing  out  these  pins,  the  watch  may  be 
taken  to  pieces.  The  pivots  of  the  several  wheels  being 
received  in  small  holes,  made  in  these  plates,  they,  of 
course,  fall  to  pieces,  as  soon  as  the  plates  are  separated. 

The  maintaining  power  is  a  spiral  steel  spring,  which 
is  coiled  up  close,  by  a  tool  used  for  the  purpose,  and  put 
into  a  brass  box,  called  the  barrel.     It  is  marked  A,  in 


DESCRIPTION   OF  A  WATCH.  201 

all  the  figures,  and  is  shown  separate,  in  Fig.  5,  with  the 
spring  in  it.  The  spring  has  a  hook,  at  the  outer  end  of 
its  spiral,  which  is  put  through  a  hole,  [a,]  Fig.  5,  in  the 
side  of  the  barrel,  and  riveted  fast  to  it.  The  inner  end 
of  the  spiral  has  an  oblong  opening,  cut  through  it,  to 
receive  a  hook  upon  the  barrel  arbor,  B,  Fig.  5.  The 
pivots  of  this  arbor  pass  through  the  top  and  bottom  of 
the  barrel,  and  one  of  them  is  filed  square,  to  hold  a 
ratchet-wheel,  [6,]  Figs.  1  and  6,  which  has  a  click,  and 
keeps  the  arbor  from  turning  round,  except  in  one  direc- 
tion. The  two  pivots  of  the  arbor  are  received  in  pivot- 
holes  in  the  plates,  CD,  of  the  watch,  and  the  pivot,  which 
has  the  ratchet-wheel  upon  it,  passes  through  the  plate. 
The  wheel  marked  [6,]  Figs.  1  and  6,  with  its  chck,  is, 
therefore,  on  the  outside  of  the  pillar-plate,  D,  of  the 
watch.  The  top  of  the  barrel  has  a  cover,  or  lid,  fitted 
into  it,  through  which  the  upper  pivot  of  the  arbor  pro- 
jects ;  thus,  the  arbor  of  the  barrel  is  to  be  considered  as 
a  fixture,  the  click  of  the  ratchet-wheel  preventing  it  from 
turning  round,  while  the  interior  end  of  the  spiral  spring, 
being  hooked,  assists  in  rendering  it  stationary.  The 
barrel,  thus  mounted,  has  a  small  steel  chain,  [f/,]  Figs. 
2  and  6,  coiled  round  its  circumference,  and  attached  to 
it  by  a  small  hook  of  the  chain,  which  enters  a  little  hole, 
made  in  the  circumference  of  the  barrel,  at  its  upper  end. 
The  other  extremity  of  this  chain  is  hooked  to  the  lower 
part  of  the  fusee,  marked  F,  Figs.  2,  5,  and  6,  and  the 
chain  is  disposed,  either  upon  the  circumference  of  the 
barrel,  or  in  the  spiral  groove,  cut  round  the  fusee  for  its 
reception,  the  arbor  of  which  has  pivots  at  the  ends,  which 
are  received  into  pivot-holes,  made  in  the  plates  of  the 
watch.  One  pivot  is  formed  square,  and  projects  through 
the  plate,  to  fit  the  key,  by  which  the  watch  is  wound  up. 
It  is  evident,  that,  when  the  fusee  is  turned  by  the 
watch-key,  it  will  wind  the  chain,  off  the  circumference 
of  the  barrel,  on  itself;  and,  as  the  outer  end  of  the  spring 
is  fastened  to  the  barrel,  and  the  other  is  hooked  to  the 
barrel-arbor,  which,  as  before  mentioned,  is  prevented 
from  turning,  by  the  click  of  the  ratchet-wheel,  [a^,]  the 
spring  will  be  coiled  up  into  a  smaller  compass  than  be- 


202  AKTS   OF  HOROLC»¥. 

fore.  Its  reaction,  therefore,  when  the  key  is  taken  off, 
will  turn  the  barrel,  and,  by  the  chain,  turn  the  fusee,  and 
give  motion  to  the  wheels  of  the  watch.  The  fusee  has 
a  spiral  groov^e  cut  round  it,  in  which  the  chain  lies  ;  this 
groove  is  cut  by  an  engine,  in  such  a  form,  that  the  chain 
shall  pull  from  the  smallest  part,  or  radius,  of  the  fusee, 
when  the  spring  is  quite  wound  up,  and,  therefore,  acts 
with  its  greatest  force  on  the  chain.  From  this  point, 
the  groove  gradually  increases  in  diameter,  so  that,  as  the 
spring  unwinds,  and  acts  with  less  power,  the  chain  oper- 
ates on  a  larger  radius  of  the  fusee  ;  and  the  effect,  upon 
the  arbor  of  the  fusee,  or  the  toothed  wheel  attached  to 
it,  will  always  be  equal,  and  cause  the  watch  to  go  with 
regularity. 

To  prevent  too  much  chain  being  wound  upon  the  fu 
see,  and,  by  that  means,  breaking  the  chain,  or  over- 
straining the  spring,  a  contrivance,  called  a  guard-gut^  is 
added.  It  is  a  small  lever,  [e,]  Fig.  2,  moving  on  a 
stud,  fixed  to  the  upper  plate,  C,  of  the  watch,  and  press- 
ed downwards  by  a  small  spring,  [/.]  As  the  chain  is 
wound  up,  upon  the  fusee,  it  rises  in  the  spiral  groove,  and 
lifts  up  the  lever,  until  it  touches  the  upper  plate.  It  is 
then  in  a  position  to  intercept  the  edge,  or  tooth,  [^,]  of 
the  spiral  piece  of  metal,  seen  on  the  top  of  the  fusee,  and 
thus  stops  it  from  being  wound  up  any  further. 

The  power  of  the  spring  is  transmitted  to  the  balance, 
by  means  of  several  toothed  wheels,  which  multiply  the 
number  of  revolutions,  which  the  chain  makes  on  the  fu- 
see, to  such  a  number,  that,  though  the  last,  or  balance- 
wheel,  turns  nine  and  one  half  times  every  minute,  the  fu- 
see will,  at  the  same  time,  turn  so  slowly,  that  the  chain 
will  not  be  drawn  off  from  it,  in  less  than,  twenty-eight  or 
thirty  hours,  and  it  will  make  only  one  turn,  in  four  hours 
This  assemblage  of  wheels  is  called  the  train  of  the 
watch.  The  first  toothed  wheel,  G,  is  attached  to  the 
fusee,  and  is  called  the  great  wheel.  It  is  shown  separa- 
ted from  the  fusee,  in  Fig.  4,  having  a  hole  through  the 
centre,  to  receive  the  arbor  of  the  fusee,  and  a  projecting 
ring  upon  its  surface.  The  under  surface  of  the  base  of 
the  fusee  is  shown  in  Fig.   5,  at  F,  having  a  circular 


DESCRIPTION  OF  A  WATCH.  203 

cavjiy  cut  in  it,  to  receive  the  corr^|ponding  ring  upon 
the  great  wheel,  G,  Fig.  4.  A  ratchet-wheel  [i]  is 
fixed  fast  upon  the  fusee  arbor,  and  sunk  within  the  cav- 
ity, excavated  in  the  lower  surface  of  the  fusee.  When 
the  wheel  and  fusee  are  put  together,  a  small  chck,  [/i,] 
Fig.  4,  takes  into  the  teeth  of  the  ratchet,  [i.]  As  the 
/iisee  is  turned  by  the  watch-key,  to  wind  up  the  watch, 
tl.s  click  slips  over  the  sloping  slides  of  the  teeth,  with- 
out turning  the  great  wheel  ;  but,  when  the  fusee  is  turned 
the  other  way,  by  drawing  the  chain  from  the  spring-bar- 
rel, the  click  catches  the  teeth  of  the  ratchet-wheel,  and 
causes  the  toothed  wheel  to  turn  with  the  fusee. 

The  great  wheel ^  G,  has  forty-eight  teeth  on  its  cir- 
cumference, which  take  into,  and  turn,  a  pinion  of  twelve 
teeth,  fixed  on  the  same  arbor  with  the 

Centre-wheel^  H,  so  called,  from  its  5atuation  in  the 
centre  of  the  watch  ;  it  has  fifty-four  teeth,  to  turn  a  pin- 
ion of  six  leaves,  on  the  arbor  of  the 

Third  wheel,  I,  which  has  forty-eight  teeth.  It  is  sunk 
ni  a  cavity,  formed  in  the  pillar-plate,  and  turns  a  pinion 
of  six,  on  the  arbor  of  the 

Contrate-wheel,  K,  which  has  forty-eight  teeth,  cut 
parallel  with  its  axis,  by  which  it  turns  a  pinion  of  six 
leaves,  fixed  to 

The  halance-wheel,  L.  One  of  the  pivots  of  the  arbor 
of  this  wheel  turns  in  a  frame,  M,  called  the  pottance,  or 
potence,  fixed  to  the  upper  plate,  and  shown  separately,  in 
Fig.  4.  The  other  pivot  runs  in  a  small  piece,  fixed  to 
the  upper  part,  called  the  counter  potlance,  not  shown  in 
any  of  the  figures  ;  so  that,  when  the  two  plates  are  put 
together,  the  balance-wheel  pinion  may  work  into  the 
teeth  of  the  contrate- wheel,  as  shown  in  Fig.  6.  The 
balance-wheel,  L,  has  fifteen  teeth,  by  which  it  impels 
the  balance,  [op.]  The  arbor  of  the  balance,  which  is 
called  the  verge,  has  two  small  leaves,  or  pallets,  projec- 
ting from  it,  nearly  at  right  angles  to  each  other.  These 
are  acted  upon  by  the  teeth  of  the  balance-wheel,  L,  in 
such  a  manner,  that,  at  every  vibration,  the  balance  re- 
ceives a  slight  impulse  to  continue  its  motion  ;  and  every 
vibration,  so  made,  suffers  a  tooth  of  the  wheel  to  escape, 


204  ARTS    OF  HOROLOGY. 

or  pass  by  ;  whMpjB  this  part  is  called  the  scapement  oi 
the  watch,  and  constitutes  its  most  essential  part.  The 
wheel,  L,  is  sometimes  called  the  scape-wheel^  or  crown- 
wheel.  Its  action  is  explained  by  Fig.  7,  which  shows 
the  wheel,  and  balance,  detached.  Suppose,  in  this  view, 
the  pinion  [h]  on  the  arbor  of  the  balance-wheel,  or 
crown-wheel,  [i/c,]  to  be  actuated  by  the  main-spring, 
which  forms  the  maintaining- power,  by  means  of  the  train 
of  wheel-work,  in  the  direction  of  the  arrow,  while  the 
pallets,  [m  and  n,]  attached  to  the  axis  of  the  balance, 
and  standing  at  right  angles  to  each  other,  or  very  nearly 
so,  are  long  enough  to  fall  in  the  way  of  the  ends  of  the 
sloped  teeth  of  the  wheel,  when  turned  round,  at  an  angle 
of  forty-five  degrees,  so  as  to  point  to  opposite  directions, 
as  in  the  figure.  Then  a  tooth  in  the  wheel  below,  for 
instance,  meets  with  the  pallet,  [n,]  supposed  to  be  at 
rest,  and  drives  it  before  it,  a  certain  space,  till  the  end 
of  the  tooth  escapes.  In  the  meantime,  the  balance, 
[ospr,']  attached  to  the  axis  of  the  pallets,  continues  to 
move  in  the  direction  [rosp,]  and  winds  up  the  small 
spiral,  or  hair-spring,  [9,]  one  end  of  which  is  fast  to 
the  axis,  and  the  other  to  a  stud,  on  the  upper  plate  of 
the  frame.  In  this  operation,  the  spring  opposes  the  mo- 
mentum, given  to  the  balance,  by  this  push  of  the  tooth 
upon  the  pallet,  and  prevents  the  balance  going  quite 
round  ;  but,  the  instant  the  tooth  escapes,  the  upper  pal- 
let [m]  meets  with  another  tooth,  at  the  opposite  side 
of  the  wheel's  diameter,  moving  in  an  opposite  direction 
to  that  below.  Here,  this  pallet  receives  a  push,  which 
carries  the  balance  back  again,  its  momentum,  as  yet, 
being  small  in  the  direction  [ospr,']  and  aids  the  spring, 
which  now  unbends  itself,  till  it  comes  to  its  quiescent 
position,  then  swings  beyond  that  point,  partly,  by  the  im- 
pulse from  the  maintaining  powder  on  the  pallet,  [m,]  and 
partly,  by  the  acquired  momentum  of  the  moving  balance, 
particularly  when  this  pallet  [m]  has  escaped.  At  length, 
the  pallet  [w]  again  meets  with  the  succeeding  tooth,  and 
is  carried  backward  by  it,  in  the  direction  in  which  the 
balance  is  now  moving,  till  the  maintaining  power  and 
force  of  the  unwound  spring,  together,  overcome  the  mo- 


DESCRIPTION   OF  A  WATCH?  205 

mentum  of  the  balance,  during  which  time,  the  recoil  of 
the  balance-wheel  is  apparent,  and,  also,  of  the  second- 
hand, if  the  watch  has  one,  its  place  being  on  the  arbor 
of  the  contrate-wheel.  Then  the  wheel  brings  the  pallet 
[n]  back  again,  till  it  escapes  ;  and  the  same  process  takes 
place  w^ith  the  pallet,  [??i,]  as  has  been  described  with  re- 
spect to  pallet,  [n.]  Thus,  two  contrary  excursions,  or 
oscillations,  of  the  balance  take  place,  before  one  tooth 
has  completely  escaped  ;  and,  for  this  reason,  there  must 
always  be  an  odd  number  of  teeth  in  this  wheel,  that  a 
space  on  one  side  of  the  wheel  may  always  be  opposite 
to  a  tooth  on  the  other,  in  order  that  one  pallet  may  be 
out  of  action,  while  the  other  is  in  action. 

The  upper  pivot  of  the  verge  is  supported  in  a  cover, 
screwed  to  the  upper  plate,  as  shown  at  N,  in  Fig.  6, 
which  extends  over  the  balance,  and  protects  it  from  vio- 
lence. The  lower  pivot  works  in  the  bottom  of  the  pot- 
tance,  M,  at  [?,]  Fig.  4.  The  socket,  for  the  pivot  of 
the  balance-wheel,  is  made  in  a  small  piece  of  brass,  [v,] 
which  slides  in  a  groove,  made  in  the  pottance,  as  shown 
in  Fig.  4  ;  so  that,  by  drawing  the  slide  in  or  out,  the 
teeth  of  the  balance-w^heel  shall  just  clear  one  pallet,  be- 
fore it  takes  the  other  ;  and,  upon  the  perfection  of  this 
adjustment,  which  is  called  the  scaping  of  the  watch,  the 
performance  of  it  very  greatly  depends. 

It  now  remains  to  show  the  communication  of  this  mo- 
tion to  the  hands  of  the  watch,  which  indicate  the  time 
on  the  dial-plate.  The  hands  are  moved  by  the  central 
arbor,  which  comes  through  the  pillar-plate,  and  projects 
a  considerable  length.  It  has  a  pinion  of  twelve  leaves, 
called 

The  common  pinion,  \_w,]  Fig.  6,  fitted  upon  it,  the 
axis  of  which  is  a  tube,  formed  square  at  the  end,  to  fix 
on  the  minute-hand,  W.  It  fits  tight  upon  the  projecting 
arbor  of  the  centre-wheel ;  and,  therefore,  turns  with  it, 
but  will  slip  round  to  set  the  hands,  wlien  the  watch  is 
wrong,  and  requires  to  be  rectified.  The  common  pin- 
ion is  situated  close  to  the  pillar-plate,  and  its  leaves  en- 
gage the  teeth  of 

The  minute-wheel,  X,  Figs.  1  and  6,  of  forty-eight 
II.  18  XII. 


206  ARTS   OF  HOROLOGY. 

teeth,  \^hich  is  fitted  on  a  pin  fixed  in  the  plate,  and  Its 
pinion,  [x,]  of  sixteen  leaves,  which  is  fixed  to  it,  turns 

The  hour-icheel,  Y,  of  forty-eight  teeth.  The  arboi 
of  this  is  a  tube,  which  is  put  over  the  tube  of  the  cannon- 
pinion^  carrying  the  minute-hand,  and  has  the  hour-hand, 
Z,  fixed  on  it,  to  indicate  the  time  upon  the  dial-plate. 
Thus,  by  the  cannon-pinion,  [lo,]  which  is  to  the  minute- 
wheel,  X,  as  one  is  to  four,  and  the  pinion  [x]  of  this, 
which  is  to  the  hour-wheel,  Y,  as  one  is  to  three,  the  hour- 
wheel,  Y,  and  its  hand,  [2:,]  though  concentric  with  the 
cannon-pinion  and  minute-hand,  make  but  one  revolution, 
during  twelve  revolutions  of  the  other  ;  therefore,  one 
turns  round  in  an  hour,  and  the  other  turns  round  once  in 
twelve  hours,  as  the  figures  on  the  dial  show. 

It  is  necessary  to  have  some  regulation^  by  which  the 
rate  of  the  watch's  movement  may  be  adjusted  ;  for,  hith- 
erto, we  have  only  spoken  of  making  the  watch  keep  al- 
ways to  a  uniform,  or  certain  rate  of,  motion  ;  but  it  is 
necessary  to  make  it  keep  true  time.  This  can  be  done 
by  two  means  ;  either  by  increasing  or  diminishing  the 
force  of  the  main-spring,  which  increases  or  diminishes 
die  arc  which  the  balance  describes  ;  or  it  may  be  done, 
by  strengthening  or  weakening  the  hair-spring,  which  will 
cause  the  balance  to  move  quicker  or  slower. 

The  hair-spring,  otherwise  called  the  pendulum- springs 
[</,]  Fig.  3,  is  fixed  to  a  stud,  upon  the  plate,  [c,]  by 
one  end,  and  is  attached  to  the  verge  of  the  balance,  by 
the  other. 

The  regulation  is  effected  by  means  of  what  is  called 
the  curb.  This  is  a  small  lever,  [r,]  Fig.  3,  projecting 
frorr.  a  circular  ring,  [rr,']  which  may  be  considered  as 
its  centre  of  motion,  but  perforated  with  a  hole  through 
the  centre,  large  enough  to  contain  the  hair-spring  within 
it.  A  circular  groove  is  turned  out  in  the  upper  plate, 
nearly  concentric  with  the  balance,  and  the  ring  [rr] 
fits  into  this.  Both  are  turned  rather  largest  at  the  bot- 
tom, in  the  manner  of  a  dove-tail  ;  but  the  ring,  being 
divided  at  the  side,  opposite  to  the  lever,  [r,]  can  be 
sprung  up,  and  rendered  so  much  smaller,  as  to  get  it 
into  the  groove  ;  and,  being  once  in,  the  elasticity  of  the 


DESCRIPTION  OF  A  WATCH.  207 

ring  expands  it,  so  as  to  fill  the  groove  completely.  In 
this  state,  it  may  be  considered  as  a  lever,  which  describes 
a  circuit  romid  the  verge,  as  a  centre  ;  and  the  end  of  it 
points  to  a  divided  arc,  engraved  on  the  upper  plate,  one 
end  of  which  is  marked  F,  and  the  other,  S,  denoting  that 
the  index,  or  lever,  [r,]  is  to  be  moved  towards  one  or 
the  other,  to  make  the  watch  move  faster  or  slower,  as 
its  regulation  requires. 

The  manner  of  its  operation  is  thus  ;  the  end  of  the 
lever,  or  index,  [2:,]  continues  within  the  circle,  a  small 
distance  towards  its  centre,  and,  passing  beneath  the  outer 
turn  of  the  spiral  spring,  [^,]  has  two  very  small  pins 
rising  up  from  it,  which  include  the  spring  between  them. 
The  actual  length  of  the  hair-spring  is,  therefore,  to  be 
estimated  from  these  pins,  to  the  place  of  its  connexion 
with  the  verge.  Now,  by  altering  the  position  of  the  in- 
dex, this  acting  length  can  be  regulated,  at  pleasure,  to 
produce  such  vibration  of  the  balance,  as  will  make  the 
watch  keep  true  time.  By  shortening  the  length,  the 
spring  becomes  more  powerful,  and  returns  the  balance 
quicker,  so  that  it  will  vibrate  in  less  time.  This  is  effec- 
ted by  moving  the  index  towards  F.  On  the  other  hand, 
turning  the  index  towards  S,  lengthens  the  spring,  by 
which  it  becomes  more  delicate,  and  less  powerful,  re- 
turning the  balance  slower  than  before. 

Many  watches,  instead  of  the  arc  and  index,  have  a 
circular  curb,  or  regulator,  which  is  turned  by  a  central 
arbor,  to  which  the  watch-key  is  applied,  when  it  is  ne- 
cessary to  move  it. 

Delicate  watches  have  jewelled  pivot-holes,  for  the  top 
and  bottom  of  the  verge,  to  diminish  the  friction.  These 
jewels  are  diamonds,  rubies,  and  other  stones,  which  unite 
great  hardness  with  durabihty.  Each  consists  of  two 
pieces,  one  of  which  has  a  cylindrical  hole  drilled  through 
it,  to  receive  the  pivot,  the  other  is  a  flat  piece,  making 
the  rest,  or  stop,  which  forms  the  bottom  of  the  hole 
Both  stones  are  ground  circular  on  the  edge,  and  are  fit- 
ted and  burnished  into  small  brass  rings,  which  are  fast- 
ened into  the  bearings,  above  and  below,  by  two  small 
screws,  applied  to  each.      The  addition  of  jewels  to  a 


208  ART      OF  METALLURGY. 

watch  is  a  great  advantage,  as  they  do  not  tendto  thicken 
the  oil,  which  brass  is  apt  to  do,  in  consequence  of  the 
oxidation  of  the  metal. 

Mr.  Dent,  a  lecturer  before  the  Royal  Institution,  ex- 
hibited to  his  audience,  a  dissected  watch,  showieg  the 
complicated  nature  of  this  little  machine.  It  appears,  that 
the  number  of  pieces,  in  a  complete  lever  watch,  is  nine 
hundred  and  ninety-two,  and  the  number  of  separate  trades, 
employed  in  manufacturing  these  pieces,  and  in  putting 
them  together,  is  forty-three. 

Works  of  Referek-ce. — Cummings's  Elements  of  Clock  and 
Watch  Work,  4to.  1766  ; — Berthoud,  Historie  de  la  Mesure  du 
Temps  par  les  Horloges,  2  torn.  4to.  1802  ; — Harrison,  on  Clock 
Work  and  Music,  8vo.  1775  ; — Robison's  Mechanical  Philosophy, 
article  Watch  Work,\o\.  iv.  ; — Martin's  Circle  of  Mechanical  Arts, 
4to.  1818  ; — and  the  Encyclopedias  of  Brewster,  Rees,  and  Nich- 
olson, under  various  heads. 


CHAPTER  XX. 

ARTS  OF  METALLURGY. 

Extraction  of  Metals,  Assaying,  Alloys.  Gold,  Extraction,  C^ipeha 
tion.  Parting,  Cementation,  Alloy,  Working,  Gold  Beating,  Gilding 
on  Metals,  Gold  Wire.  Silver,  Extraction,  Working,  Coining,  Plat- 
ing. Copper, Extraction,  Working.  2?rass,  Manufacture,  Buttons, 
Pins,  Bronze.  Lead,  Extraction,  Manufacture,  Sheet  Lead,  Lead 
Pipes,  Leaden  Shot.  Ti?i,  Block  Tin,  Tin  Plates,  Silvering  of  Mir- 
rors. Iroii,  Smelting,  Crude  Iron,  Casting,  ^Malleable  Iron,  Forg- 
ing, Rolling  and  Slitting,  Wire  Drawing,  Nail  Making,  Gun  Ma'-ing. 
Steel,  Alloys  of  Steel,  Case  Hardening,  Tempering,  Cutlery. 

The  term  metallurgy,  in  its  most  comprehensive  sen«e, 
signifies  the  art  of  working  metals,  in  every  different  way. 
In  a  more  precise  and  limited  sense,  it  is  confined  to  the 
separating  of  metals  from  their  ores,  and  assaying  them, 
to  ascertain  their  value.  In  the  present  chapter,  it  is  pro- 
posed to  make  use  of  the  term  in  its  more  general  mean- 
ing ;  so  far,  at  least,  as  to  comprehend  certain  processe*^ 


EXTRACTION  OP  METALS.  209 

in  the  management  and  manufacture  of  metals,  which  are 
sufficiently  interesting,  to  merit  the  attention  of  the  general 
student. 

Extraction  of  Metals. — Metals  are  found  in  Nature,  m 
various  states.  When  uncombined,  or  when  combined 
only  with  each  other,  they  are  said  to  be  in  a  native  state. 
When  combined  with  other  substances,  so  that  the  me- 
tallic properties  are.,  in  some  measure,  disguised,  they 
are  said  to  be  mineralized,  or  in  the  state  of  ore.  The 
substance,  with  which  the  metal  is  combined,  is  termed 
its  mineralizer.  The  most  common  states  of  combina- 
tion, in  which  the  metallic  ores  are  found,  are  oxides, 
combinations  of  oxides  with  carbonic,  sulphuric,  muriatic, 
and  phosphoric,  acids  and  sulphurets.  These  ores  oc- 
cur, under  various  forms,  sometimes  crystallized,  and  often 
destitute  of  any  regular  figure.  They  are  met  with,  gen- 
erally, in  veins,  penetrating  the  strata  ;  and,  in  this  case, 
are  usually  blended,  or  intermixed,  with  various  earthy 
fossils,  as  calcareous  spar,  fluor  spar,  quartz,  &c.  The 
accompanying  fossil  is  termed  the  gangue^  or  matrix,  of 
the  metal.  Some  metallic  ores  occur  in  beds,  or  in  large 
insulated  masses. 

To  separate  the  metal,  after  it  is  dug  from  the  mine, 
the  mass  is  broken  up,  and  subjected  to  the  operations 
of  sorting,  stamping,  washing,  roasting,  smelting,  and  re- 
fining. Sorting  consists  merely  in  the  separation  of  the 
different  pieces  of  ore,  into  lots,  according  to  the  products 
they  are  expected  to  afford,  and  the  treatment  they  are 
likely  to  require.  After  the  ore  is  sorted,  it  is  carried  to 
the  stamper,  or  stamping-mill,  which  has  been  described 
in  a  former  chapter.  The  process  of  stamping,  breaks 
and  pounds  up  the  ore,  together  with  its  gangue,  into  a 
coarse  powder.  From  the  stamping-mill,  the  pounded 
ore  is  conveyed  to  the  icashing ;  a  process,  in  which  ad- 
vantage is  taken  of  the  difference  of  specific  gravity.  The 
operation  of  w^ashing  is  sometimes  performed  by  hand,  in 
wooden  vessels,  or  in  troughs,  which  cross  a  current  of 
water  ;  and,  sometimes,  if  the  ore  is  rich,  and  valuable, 
upon  inclined  tables,  covered  with  cloth.  In  this  pro- 
cess, the  heavier  parts,  consisting  of  the  metaUic  ore, 
18* 


210  ARTS   OF  METALLURGY 

sink  first  to  the  bottom,  while  the  stony  matter,  which  is 
lighter  than  the  ore,  being  longer  in  sinking,  is  carried 
further  down  the  current,  and  thus  separated  from  the  rest. 

The  next  operation,  which  is  that  of  roasting^  is  em- 
ployed to  drive  off  the  sulphur,  arsenic,  and  other  volatile 
parts,  which  the  mineral  may  contain.  It  is  performed 
in  a  variety  of  ways,  and  by  different  processes,  accor- 
ding to  the  nature  of.  the  ore,  and  the  degree  of  heat  re- 
quired. The  roasting  is  sometime  performed  in  the  air, 
and  sometimes,  in  furnaces,  among  the  fuel.  Smelting 
consists,  in  general,  in  fusing  the  roasted  ore,  with  a  view 
to  extract  the  metal ;  though  the  term  is  sometimes  ap- 
plied to  the  melting  of  metal,  in  any  state,  especially  iron 
The  immediate  object  of  this  process  is  to  reduce  the 
metal,  or  to  separate  the  oxygen,  with  which  the  metal 
has  either  been  naturally  combined,  or  has  united,  during 
the  operation  of  roasting.  This  is  done,  by  placing  in  a 
furnace,  alternate  layers  of  charcoal,  or  coke,  and  of  the 
metallic  matter  ;  a  strong  heat  is  then  excited  by  bellows  ; 
the  carbonaceous  matter  attracts  the  oxygen,  while  the 
metal  is  reduced,  melted,  and  run  out,  at  the  bottom  of 
the  furnace.  The  volatile  metals  are  obtained  by  subli- 
mation, or  distillation.  Even  after  these  operations,  the 
metal  is  seldom  pure,  but  is  combined  with  some  other 
metal  or  metals,  which  have  been  present  in  the  ore.  If 
these  are  in  small  quantity,  and  do  not  injure  the  metal, 
they  are  in  general  disregarded.  If  it  is  necessary,  how- 
ever, to  separate  them,  or  if,  from  their  value,  the  sep- 
aration is  an  object  of  importance,  different  processes  are 
followed,  adapted  to  each  particular  metal.  All  the  op- 
erations, subsequent  to  smelting,  are  comprehended  under 
the  general  name  of  refining^  because  their  effect  is  always 
to  obtain  a  purer  metal.  The  difierent  metals  are  refined 
by  different  processes. 

Assaying. — The  art  of  assaying  metallic  ores  is  that 
of  analyzing  them,  in  small  quantities,  so  as  to  discover 
their  component  parts.  It  requires  a  knowledge  of  the 
relations  of  the  metals  to  the  other  chemical  agents,  and 
is  varied,  in  its  different  stages,  as  applied  to  each.  The 
general  process  consists,  in  selecting  proper  specimens  of 


ALLOYS.  211 

the  ore,  which  is  done,  by  taking  equal  portions  of  that 
which  appears  to  be  the  richest,  the  poorest,  and  of  me- 
dium value,  and  reducing  these  to  coarse  powder,  w^hich 
is  washed,  to  carry  off  any  earthy  or  stony  matter.  It 
is  then  roasted  in  a  shallow  earthen  vessel,  under  a  muffle, 
to  expel  the  volatile  principles.  It  is  lastly  reduced,  by 
mixing  it  with  fluxes,  and  applying  a  more  or  less  intense 
heat,  as  the  metal  is  more  or  less  refractory.  The  me- 
tallic matter,  existing  in  the  ore,  is  thus  obtained.  This, 
it  is  obvious,  may  consist  of  various  metals  ;  and,  if  there 
is  reason  to  beheve  this, 'and  it  be  of  importance  to  ascer- 
tain it,  it  is  submitted  to  operations,  adapted  to  the  metals 
which  may  be  supposed  present.  Sometimes,  an  accu- 
rate analysis  is  made,  at  once,  of  the  metalhc  ore,  in  the 
humid  way ;  the  metal  being  dissolved  by  the  different 
acids,  and  precipitated  by  the  alkalis,  earths,  and  other 
re-agents.  The  assaying  of  the  precious  metals  is  usual- 
ly confined  to  ascertaining  the  quantity  of  gold  or  silver, 
in  any  alloy  or  compound,  without  regard  to  the  other 
constituents. 

Alloys.-^The  metals  are  capable  of  combining  with 
each  other,  by  fusion  ;  and  to  these  combinations,  the  name 
of  alloy  is  given.  They  all  retain  the  general  metalhc 
properties, — lustre,  opacity,  and  density ;  and  even,  in  the 
greater  number  of  cases,  the  properties  of  the  constituent 
metals  remain  in  the  combination,  only  somewhat  modi- 
fied. In  general,  alloys  are  more  hard  and  brittle  than 
the  individual  metals  of  which  they  consist,  though  this, 
as  well  as  the  other  changes  of  properties,  is  considerably 
influenced  by  the  proportions,  in  which  the.  ingredients  are 
combined.  They  have  also,  in  general,  a  greater  fusi- 
bility, than  the  mean  fusibihty  of  the  respective  metals. 
The  alloys  of  quicksilver,  called  amalgams^  are  usually 
soft,  or  liquid,  according  to  the  proportions.  The  metals 
combined  in  alloys,  are  generally  more  susceptible  of  ox- 
idizeraent,  than  in  their  separate  state  ;  owing,  probably, 
to  the  diminution  in  the  power  of  cohesion,  by  the  com- 
bination, or,  perhaps,  to  an  electrical  action.  From  their 
peculiar  properties,  some  of  the  alloys  are  extensively 
used,  as  brass,  which  is  an  alloy  of  copper  and  zinc  ;  and 
Dewter,  which  is  an  alloy  of  tin  and  zinc  or  lead. 


212  ARTS   OF  METALLURGY. 

A  degree  of  condensation  usually  attends  these  combi- 
nations, so  that  the  specific  gravity  of  the  alloy  is  greater, 
than  the  mean  specific  gravity  of  its  constituent  metals. 
In  brass,  for  example,  it  is  one  tenth  greater,  and,  in 
some  cases,  the  condensation  is  such,  that  the  density  is 
even  greater  than  that  of  the  heavier  metals  combined,  as 
in  the  alloy  of  silver  and  quicksilver.  Sometimes,  how- 
ever, the  particles  assume  such  an  arrangement,  that  the 
density  is  less  than  the  mean,  as  in  the  examples  of  the 
alloy  of  copper  with  silver,  and  of  gold  with  tin,  and  gold 
with  iron. 

In  these  combinations,  there  exists  a  certain  order  of 
attractions,  by  which  one  metal  is  more  disposed  to  unite 
with  another,  than  a  third  is.  The  difference,  however,  is 
not  very  considerable  ;  hence,  three,  four,  or  more,  metals 
can  be  combined  together.  Some,  however,  are  difficult 
to  unite,  as  iron  and  lead,  and  iron  and  quicksilver.  The 
combination  seems  to  be,  in  some  measure,  regulated  by 
the  relations  of  fusibility  and  specific  gravity  ;  so  that,  the 
affinities  being  equal,  the  metals  are  less  disposed  to  com- 
bine, as  they  differ  more  in  their  fusibihty  and  specific 
gravity  ;  and,  where  the  affinity  is  weak,  a  considerable 
difference  of  this  kind  may  prevent  any  combination  what- 
ever. 

GOLD. 

Gold  exists  in  various  minerals  ;  but  the  greatest  part 
of  the  gold,  in  the  possession  of  mankind,  has  been  found 
in  the  form  of  grains  and  small  masses,  among  the  alluvial 
sands,  which  constitute  certain  plains,  and  margins  of  riv- 
ers. In  this  state,  it  is  usually  alloyed  with  small  por- 
tions of  other  metals,  particularly  silver  and  copper. 

Extraction. — When  native  gold  is  found  in  a  state  of 
m'lxture  with  foreign  matters,  its  extraction  is  commonly 
performed  by  amalgamation  with  quicksilver.  After  hav- 
ing been  freed,  by  pounding  and  washing,  from  most  of  the 
stony  matter  mixed  with  it,  it  is  triturated  with  ten  times 
its  weight  of  quicksilver,  until  an  amalgam  is  formed. 
This  is  separated  from  any  superfluous  earthy  matter,  and 
subjected  to  pressure,  enclosed  in  leather,  by  which  the 


CUPELLATION. PARTING.  213 

more  fluid  part  is  separated,  and  forced  through  the  leath- 
er, while  the  more  consistent  amalgam,  containing  the 
greater  part  of  the  gold,  remains.  It  is  then  subjected  to 
distillation,  in  retorts  of  earthen  ware,  to  separate  the 
quicksilver,  and  the  remaining  gold  is  afterwards  fused. 
When  the  gold  is  contained  in  other  ores,  the  ore  is 
roasted,  to  drive  off  the  more  volatile  principles,  and  to 
oxidize  the  other  metals.  The  gold  is  then  extracted,  by 
amalgamation,  by  liquefaction  with  lead,  by  the  action  of 
nitric  acid,  or  other  methods,  adapted  to  each  ore,  accor- 
ding to  its  constituent  parts. 

Cupellation. — Gold,  obtained  in  any  of  these  ways,  is 
always  more  or  less  alloyed,  particularly  with  silver  or 
copper.  The  first  step  in  its  purification  is  the  process 
of  cupellation.  To  explain  the  nature  of  this,  it  is  neces- 
sary to  observe,  that  lead  is  a  metal  very  fusible,  and  ex- 
tremely easy  of  oxidizement,  forming  an  oxide,  which  easi- 
ly vitrifies,  and  which  favors  the  oxidizement  and  vitrifica- 
tion of  other  metals.  A  portion  of  lead,  therefore,  is  ad- 
ded to  the  impure  gold,  more  or  less,  according  to  the 
quantity  of  alloy  which  it  contains,  of  which  the  work- 
man judges  by  the  color,  hardness,  elasticity,  and  specific 
gravity,  of  the  gold.  They  are  melted  together,  and  ex- 
posed to  heat  on  a  cupel,  which  is  a  vessel  made  of  bone- 
ashes,  or,  sometimes,  of  wood-ashes,  under  a  muffle,  or, 
in  the  large  way,  on  the  hearth  of  a  refining  furnace. 
The  lead  passes  to  the  state  of  oxide,  is  vitrified,  and,  at 
the  same  time,  promotes  the  oxidizement  and  vitrification 
of  the  foreign  metals.  The  vitrified  oxide  is  absorbed 
by  the  porous  cupel,  or,  in  the  large  way,  the  greater 
part  is  driven  off  by  the  blast  of  bellows,  and  removed. 
When  the  greater  part  of  the  foreign  metals  is  abstracted, 
the  remaining  fused  metal  exhibits  various  prismatic  col- 
ors, which  succeed  each  other  quickly.  It  at  length  sud- 
denly brightens,  and  its  surface  becomes  highly  luminous. 
This  IS  regarded  as  the  completion  of  the  process.  The 
metal  is  allowed  to  become  solid,  and,  while  yet  hot,  is 
detached. 

Parting. — The  gold,  even  after  having  been  submitted 
to  this  process,  may  still  be  alloyed  with  silver,  which, 


214  ARTS   OF  METALLURGY. 

being  nearly  as  difficult  of  oxidizement,  is  not  removed 
by  the  action  of  the  lead.  It  is,  therefore,  lastly  sub- 
jected to  the  operation  of  parting.  The  metal  is  rolled 
out  thin,  and  cut  into  small  pieces.  These  are  digested 
with  a  moderate  heat,  in  diluted  nitric  acid,  which  dis- 
solves the  silver,  leaving  the  gold,  undissolved,  in  a  por- 
ous mass.  It  has  been  found,  however,  that,  when  the 
proportion  of  silver  is  small  to  that  of  gold,  the  latter 
protects  the  former  from  the  action  of  the  acid  The 
previous  step  of  quartation,  as  it  is  named,  is  therefore 
employed,  which  consists  in  fusing  three  parts  of  silver 
with  one  of  the  gold,  and  then  subjecting  this  alloyed 
metal,  rolled  out,  to  the  operation  of  the  acid.  These 
are  the  operations  employed  in  commerce.  To  obtain 
gold,  perfectly  pure,  still  another  process  is,  perhaps,  nec- 
essary,— dissolving  it  in  nitro-muriatic  acid,  and  adding 
to  the  solution,  a  solution  of  sulphate  of  iron,  which,  at- 
tracting the  oxygen,  precipitates  the  gold,  in  the  metallic 
state. 

Cementation. — The  process  of  cementation  is  per 
formed,  by  beating  the  alloy  into  thin  plates,  and  placing 
these  in  alternate  layers,  with  a  cement,  containing  nitrate 
of  potass,  and  sulphate  of  iron.  The  whole  is  then  ex- 
posed to  heat,  until  a  great  part  of  the  alloying  metals 
are  removed,  by  the  action  of  the  nitric  acid,  which  is 
liberated  by  the  nitre.  Cementation  is  sometimes  em- 
ployed, by  goldsmiths,  to  refine  the  surface  o^ articles,  in 
which  gold  is  alloyed  with  baser  metals. 

Alloy. — There  is  a  peculiar  language,  established  in 
commerce,  and  often  referred  to,  by  WTiters,  to  denote 
the  purity  of  gold,  or  the  degree  of  its  alloy  with  other 
metals.  The  mass  is  supposed  to  consist  of  twenty-four 
equal  parts,  these  imaginary  parts  being  termed  carats. 
If  perfectly  pure,  or  unalloyed,  it  is  said  to  be  gold  twen- 
ty-four carats  fine  ;  if  alloyed  with  one  part  of  any  other 
metal,  or  mixture  of  metals,  it  is  said  to  be  twenty-three 
caiats  fine.  In  this  way,  the  proportion  of  alloy  is  ex- 
pressed. The  standard  gold  coin  of  the  United  States, 
and  Great  Britain,  is  twenty- two  carats  fine  ;  or  contains 
one  twelfth  part  of  alloy. 


WORKING. GOLD-BEATING.  215 

Gold,  when  perfectly  pure,  is  not  so  fit  for  coin,  on 
account  of  its  softness,  in  consequence  of  which,  the  im- 
pression is  soon  obliterated,  and  it  sustains  loss  from  fric- 
tion. Hence,  it  is  always  alloyed,  to  give  it  hardness. 
The  metals,  that  have  been  used  for  this  purpose,  are  sil- 
ver or  copper.  Gold,  made  standard  by  an  alloy,  con- 
sisting of  equal  parts  of  silver  and  copper,  has  a  color, 
approaching  more  to  that  of  pure  gold,  than  any  other 
alloy.  This  color  also  remains  uniform,  while  that  with 
copper,  after  a  certain  degree  of  wear,  becomes  une- 
qual.*       • 

Working. — Common  goldsmiths'  work  is  performed, 
by  casting  in  moulds,  beating  with  hammers,  and  rolling 
between  polished  steel  rollers.  Works,  that  have  raised 
or  embossed  figures,  are  commonly  cast  in  moulds,  and 
afterwards  polished  ;  or,  they  are  struck  in  dies,  cut  for 
the  purpose.  Vessels,  both  of  gold  and  silver,  are  beat 
out  from  flat  plates.  When  the  form  is  difficult,  they 
are  made  of  several  plates,  and  soldered  together.  The 
solder  used  for  this  purpose,  is  an  alloy  of  gold  with  si. 
v^er,  copper,  or  brass.  Small  ornamental  works  are 
commonly  executed,  by  enchasing.  This  process  is  per- 
formed upon  thin  plates  of  gold,  W'ith  a  block  and  ham- 
mer. It  consists,  in  driving  in  portions  of  the  metal,  on 
one  side,  in  such  a  manner,  that  they  stand  in  relief,  form- 
ing the  figures  required,  on  the  opposite  side.  Many 
small  articles  are  also  made  from  gold  wire,  variously 
ft^rought  and  ornamented. 

Gold  Beating. — The  great  utility  of  gilding,  in  the 
urts,  in  furnishing  an  incorruptible    covering  to  various 

*  Mr.  Hatchet,  with  Mr.  Cavendish,  subjected  the  different  alloys 
ihat  have  been  used  as  coin,  to  friction,  as  similar  as  possible  to  that 
to  which  they  must  be  subjected,  in  the  course  of  circulation.  The 
loss  was  by  no  means  considerable  ;  and  it  appeared,  as  the  general 
result,  that  the  present  standard  of  gold,  or  an  alloy  of  one  part  in 
twelve,  is,  all  circumstances  considered,  the  best,  or  at  least,  as  good 
as  any,  that  could  be  chosen.  If  the  copper  be  in  larger  proportions, 
more  loss  is  sustained,  from  friction.  The  same  alloy  is  employed  in 
the  fabrication  of  plate,  and  of  trinkets,  and  lace,  and,  by  other  addi- 
tions, various  shades  of  color  are  obtained.  Its  alloy  with  a  fifth  of 
silver  forms  the  green  gold  of  the  jewellers^  and  the  addition  of  iron 
gives  a  blue  tint. 


216  ARTS   OF  METALLURGY. 

substances,  has  given  rise  to  an  extensive  consumption  of 
qold-leaf^  which  is  formed,  by  beating  the  metal  to  a 
state  of  extreme  tenuity.  The  gold  is  first  forged  into 
plates,  on  an  anvil,  and  then  reduced,  by  passing  it  be- 
tween polished  steel  rollers,  till  it  becomes  a  riband,  as 
thin  as  paper.  This  riband  is  divided  into  small  pieces, 
which  are  again  beat  upon  an  anvil,  till  they  are  about  an 
inch  square,  after  which,  they  are  thoroughly  annealed.* 
Two  ounces  of  gold  make  one  hundred  and  fifty  of  these 
squares.  All  these  squares  are  interlaid  with  leaves,  first 
of  vellum,  and  afterwards,  of  gold-beater's  sfcin,  a  thin 
membraneous  substance  obtained  from  the  intestines  of 
animals.  The  whole  is  then  beaten  with  a  heavy  ham- 
mer, till  the  gold  is  extended  to  the  same  size  as  the 
pieces  of  skin.  The  gold  leaves  are  then  taken  out,  and 
each  cut  into  four  parts  ;  and  the  six  hundred  pieces, 
thus  produced,  are  again  interlaid,  in  the  same  manner, 
with  skins,  and  the  beating  repeated,  with  a  hghter  ham- 
mer. They  are  afterwards. re-divided,  as  before,  and 
formed  into  parcels,  which  are  separately  beat,  at  one 
or  more  operations,  until  the  leaf  has  attained  the  requi- 
site thinness.  The  use  of  the  membranes,  which  are  in- 
terposed between  the  leaves,  is,  to  prevent  them  from  co- 
hering together,  at  the  same  time  that  they  are  permitted 
to  expand  ;  and,  also,  to  soften  the  blows  of  the  hammer. 
Notwithstanding  the  vast  extent,  to  which  gold  is  beaten 
between  these  skins,  and  the  great  tenuity  of  the  skins 
themselves,  yet  they  are  said  to  sustain  continual  repeti- 
tions of  the  process,  for  a  long  time,  without  receiving  inju- 
ry. The  kind  of  leaf,  called  party-gold,  is  formed,  by  lay- 
mg  a  thin  leaf  of  gold  upon  a  thicker  one  of  silver.  They 
are  then  heated,  and  pressed  together,  till  they  unite  and 
cohere  ;  after  which,  they  are  beaten  into  leaves,  as  before. 
Gilding  on  Metals. — Gilding  on  cc^per  is  commonly 
performed  with  an  amalgam  of  gold  and  mercury.  The 
surface  of  the  copper,  being  freed  from  oxide,  is  covered 

*  The  process  of  annealing  is  applied  to  metals,  and  some  other 
substances,  to  diminish  their  brittleness,  or  increase  their  flexibility 
and  ductility.  It  is  performed,  by  heating  the  substance,  and  suffering 
it  to  cool,  in  a  very  gradual  n)anner. 


GOLD-WIRE. SILVER  EXTRACTION.  217 

with  the  amalgam,  and  afterwards  exposed  to  heat,  till  the 
mercury  is  driven  off,  leaving  a  thin  coat  of  gold.  It  is 
also  performed,  by  dipping  a  linen  rag  in  a  saturated  solu- 
tion of  gold,  and  burning  it  to  tinder.  The  black  pow- 
der, thus  obtained,  is  rubbed  on  the  metal  to  be  gilded, 
with  a  cork  dipped  in  salt  water,  till  the  gilding  appears. 
Iron  or  steel  is  gilded,  by  applying  gold-leaf  to  the  met- 
al, after  the  surface  has  been  well  cleaned,  and  heated, 
until  it  has  acquired  the  blue  color,  which,  at  a  certain 
temperature,  it  assumes.  The  surface  is  previously  bur- 
nished, and  the  process  is  repeated,  when  the  gilding  is 
required  to  be  more  durable.  It  is  also  performed,  by  di- 
luting the  solution  of  gold  in  nitro-muriatic  acid,  with  al- 
cohol, and  applying  it  to  the  clean  surface.* 

Gold  Wire. — The  common  gold  or  gilt  wire  is,  in 
reahty,  silver  wire  covered  with  gold.  In  making  it,  a 
silver  rod  is  enclosed  in  thick  leaves  of  gold.  It  is  then 
drawn,  successively,  through  conical  holes,  of  different 
sizes,  made  in  plates  of  steel,  in  a  manner  similar  to  that 
pursued  in  making  iron  wire.  The  wire  may  thus  be  re- 
duced to  an  extreme  degree  of  fineness,  the  gold  being 
drawn  out  with  the  silver,  and  constituting  a  perfect 
coating  to  the  wnre.  When  it  is  intended  to  be  used  In 
forming  gold-thread,  the  wire  Is  flattened,  by  passing  it 
between  rollers  of  polished  steel.  The  coating  of  gold 
remains  unbroken,  though  so  far  reduced,  by  these  pro- 
cesses, as  not  to  occupy  the  millionth  part  of  an  inch  in 
thickness.  The  gold-thread,  commonly  used  in  embroi- 
dery, consists  of  threads  of  yellow  silk,  covered  by  flat- 
tened gilt  wire,  closely  wound  upon  them  by  machinery. 

SILVER. 

Extraction. — Silver  is,  in  general,  extracted  without 

*  This  last  process  has  been  improved  by  Mr.  Stoddart.  A  satura- 
ted solution  of  gold  in  nitro-muriatic  acid,  being  mixed  with  three  times 
its  weight  of  sulphuric  ether,  dissolves  the  muriate  of  gold,  and  the 
solution  is  separated  from  the  acid  beneath.  To  gild  the  steel,  it  is 
merely  necessary  to  dip  it,  the  surface  being  previously  well  polished 
and  cleaned,  in  the  etherial  solution,  for  an  instant  ;  and,  on  with- 
drawing it,  to  wash  it  instantly,  by  agitation  in  water.  By  this  method, 
steel  instruments  are  very  commonly  gilt. 

II.  19  XII. 


218  ARTS   OF  METALLURCr. 

much  difficulty.  When  native,  it  is  separated  from  the 
eartliy  matter,  by  washing,  and  amalgamation  with  mer- 
cury ;  the  latter  being  separated  again,  by  distillation. 
When  alloyed  with  antimony,  or  arsenic,  or  when  mineral- 
ized, the  ore  is  roasted,  to  expel  these  metals,  with  the 
sulphur,  or  other  volatile  principles  ;  and  the  residual  mat- 
ter is  fused  with  lead,  and  refined  by  cupellation,  in  a 
manner  similar  to  that  described  under  the  head  of  gold  ; 
the  alloy  of  lead  and  silver  being  exposed  to  heat,  on  the 
hearth  of  the  refining  furnace,  the  lead  being  oxidized 
along  with  the  foreign  metals,  the  oxidizement  and  vitrifi- 
cation of  which  it  promotes,  and  the  vitrified  oxide  being, 
in  part,  absorbed,  and,  in  part,  driven  off  by  the  blast  of 
the  bellows.  The  appearance  of  a  vivid  incandescence, 
or  brightening,  denotes  when  the  silver  has  become  suffi- 
ciently pure.  It  retains  a  little  gold  in  combination,  but 
this  does  not  alter  its  quahties  ;  and  the  quantity  is  seldom 
such,  as  to  render  its  separation,  by  the  operation  of 
parting,  an  object  of  importance. 

If  the  ore  which  is  wrought  contain  only  a  small  por- 
tion of  silver,  the  previous  operation  of  eliquation  is 
sometimes  performed  on  it.  This  consists  in  adding  a 
certain  portion  of  lead  to  the  metalhc  matter  which  re- 
mains, after  roasting,  and  fusing  the  ore.  This  alloy  is 
then  exposed  to  a  degree  of  heat,  just  sufficient  to  melt 
the  lead,  which  runs  out,  and,  from  its  affinity  to  the  sil- 
ver, carries  it  along  with  it,  leaving  the  copper,  or  other 
metals,  with  which  the  silver  had  been  combined.  The 
alloy  of  silver  and  lead  is  then  subjected  to  the  usual  re- 
fining process. 

Working. — Silver  is  cast  into  bars,  or  ingots,  and  af 
ter wards  wrought,  by  hammering  and  rolling.  The  bars 
are  beaten  upon  anvils,  being  heated,  from  time  to  time, 
to  render  them  more  ductile.  The  hammering  is  con- 
ducted, while  the  heat  is  below  redness.  They  are  then 
passed  between  polished  steel  rollers,  until  they  are  re- 
duced to  plates  of  a  suitable  thickness.  To  form  uten- 
sils of  different  kinds,-  these  plates  are  hammered  in 
moulds,  till  they  acquire  the  proper  shape.  Vessels  are 
often  made  in  pieces,  which  ar©  afterwards  united  by  sol 


COINING.  219 

derlng.  The  solder,  used  for  silver,  consists  of  an  alloy 
of  silver,  with  more  than  an  equal  part  of  copper  or  brass. 
Figures,  which  are  raised  upon  the  silver,  are  produced 
by  hammering  the  metal  upon  steel  dies,  in  which  the 
figure  is  cut,  or  by  passing  it  through  engraved  rollers. 
Silver  is  polished,  by  burnishing  it  with  steel  instruments, 
or  with  hard  polished  stones  ;  and  by  rubbing  it  with  the 
oxide  of  iron,  called  colcothar^  in  fine  powder. 

Silver,  in  the  arts,  is  usually  alloyed  with  a  little  cop 
per,  which  increases  its  hardness,  and  renders  it  more 
sonorous,  without  debasing  its  color.  The  standard  sil- 
ver of  the  British  coins  contains  eighteen  pennyweights 
of  copper,  in  a  pound  Troy  of  silver  ;  and,  in  the  Uni- 
ted States,  sixteen  hundred  and  sixty-four  grains  of  silver 
contain  one  hundred  and  seventy-nine  grains  of  copper. 

Coining. — The  coining  of  silver,  and  other  metals, 
was  originally  performed  by  the  hammer,  in  matrices,  or 
dies,  engraved  for  the  purpose.  At  the  present  day, 
coins,  of  every  description,  are  more  commonly  milled. 
In  coining  by  the  mill,  the  bars  or  ingots,  of  gold  or  sil- 
ver, after  having  been  cast,  are  taken  out  of  the  moulds, 
and  their  surfaces  cleaned.  They  are  then  flattened  by 
rollers,  and  reduced  to  the  proper  thickness,  to  suit  the 
species  of  money,  about  to  be  coined.  To  render  the 
plates  more  uniform,  they  are  sometimes  wire-drawn,  by 
passing  them  through  narrow  holes,  in  a  steel  plate.  The 
plates,  whether  of  gold,  silver,  or  copper,  when  reduced 
to  their  proper  thickness,  are  next  cut  out  into  round 
pieces,  called  blanks,  or  planchets.  This  cutting  is  per- 
formed by  a  circular  steel  punch,  of  the  size  of  the  coin, 
which  is  driven  downward,  by  a  powerful  screw,  and 
passes  through  a  corresponding  circular  hole,  carrying 
before  it  the  piece  of  metal  which  is  punched  out.  The 
pieces,  which  are  thus  cut,  are  brought  to  the  standard 
weight,  if  necessary,  by  filing  or  rasping  ;  and  the  defi- 
cient pieces,  together  with  the  corners,  and  pieces  of  the 
plates,  left  by  the  circles,  are  returned  to  the  melter. 

The  milling,  by  which  the  inscription,  or  other  impres 
oion,  is  given  to  the  edge  of  the  coin,  is  perfornied,  by 
rolling  the  coin  edgewise,  between  two  plates  of  steel,  in 


220  ARTS    OF  METALLURGY. 

the  form  of  rulers,  each  of  which  contains  half  of  the  en 
graved  edging.  One  of  these  plates  is  fixed,  and  the 
other  is  movable,  by  a  rack  and  pinion.  The  coin,  being 
placed  between  them,  is  carried  along  by  the  motion  of  the 
rack,  till  it  has  made  half  a  revolution,  and  received  the 
whole  impression  on  its  edge.  The  most  important  part  of 
the  coining  still  remains  to  be  done,  and  consists  in  stamping 
both  sides,  with  the  appropriate  device,  or  figure,  in  relief. 
For  this  purpose,  the  circular  piece  is  placed  between 
two  steel  dies,  upon  which  the  figures  to  be  impressed  are 
sunk,  or  engraved,  in  the  manner  of  an  intaglio.  The 
two  dies  are  then  forcibly  pressed  together,  by  the  action 
of  a  powerful  screw,  to  which  is  attached  a  heavy  trans- 
verse beam,  which  serves  the  purpose  of  a  fly,  and  con- 
centrates the  force  at  the  moment  of  the  impression.  The 
coin  is  now  finished,  and  is  thrown  out,  when  the  screw 
rises. 

In  the  coining  machinery  erected  by  Boulton  and  Watt, 
and  introduced  at  the  mint  in  England,  the  process  is  per- 
formed by  steam-power,  and  both  the  edges  and  faces  ol 
the  money  are  coined  at  the  same  time.*  By  means  of 
this  machinery,  eight  presses,  attended  by  boys,  can 
strike  nineteen  thousand  pieces  of  money  in  an  hour,  and 
an  exact  register  is  kept  by  the  machine,  of  the  number  of 
pieces  struck. 

For  the  coining  of  medals,  the  process  is  nearly  the 
same  as  for  that  of  money.  The  principal  difference 
consists  in  this,  that  money,  having  but  a  small  relief,  re- 
ceives its  impressions  at  a  single  stroke  of  the  engine  ; 
whereas,  in  medals,  the  high  reUef  makes  several  strokes 
necessary  ;  for  which  purpose,  the  piece  is  taken  out  from 
between  the  dies,  heated,  and  returned  again.  This 
process  for  medallions  is  sometimes  repeated,  as  many  as 
a  dozen  or  more  times,  before  the  full  impression  is  given 
them.  Some  medallions,  in  a  very  high  relievo,  are 
obHged  to  be  cast  in  sand,  and  afterwards  perfected  by  be- 
ing sent  to  the  press. 

Plating. — The   great  value  of  silver,  and  the  useful 

*  A  particular  account  of  this  machinery  is  given  in  the  London 
Mechanic's  Magazine,  vol.  iii. 


PLATING.  221 

property  which  it  possesses,  of  resisting  oxidation,  has 
given  rise  to  the  art  oi platings  in  which  vessels  and  uten- 
sils of  other  metals,  but,  chiefly,  of  copper,  are  covered 
with  a  thin  coating  of  silver,  so  as  to  protect  them  from 
the  influence  of  the  atmosphere.  Plating  is  sometimes 
executed  by  heating  the  articles,  which  are  to  be  coated, 
and  rubbing  on  them  portions  of  leaf-silver,  with  a  steel 
burnisher,  till  it  adheres.  But  it  is  performed,  in  a  better 
manner,  by  plating  solid  ingots  of, copper,  and  afterwards 
working  these  into  any  shape  desired.  The  ductihty  of 
the  coating  of  silver  causes  it  to  be  extended,  and  drawn 
out  with  the  copper,  so  that  the  latter  metal  never  appears 
at  the  surface.  The  copper,  used  in  plating,  is  alloyed 
with  a  httle  brass.  Great  care  is  taken,  in  casting,  to 
form  the  ingots  sound,  and  free  from  pores,  or  flaws. 
The  surface  of  the  ingot  is  cleaned  with  a  file,  and  a  thin 
plate  of  silver  is  apphed  to  one  or  to  both  sides,  accord- 
ing to  the  article  to  be  manufactured.  A  saturated  so- 
lution of  borax  is  then  insinuated  between  the  edges,  the 
object  of  which  is,  to  protect  the  copper  from  oxidation, 
which  would  otherwise  prevent  the  silver  from  adhering. 
The  ingot  is  then  carried  to  the  furnace,  and  exposed  to 
lieat,  until  the  metals  adhere  to  each  other.  Their  adhe- 
sion is  owing  to  the  formation  of  an  alloy  between  the 
silver  and  copper,  which,  being  fusible  at  a  lower  tem- 
perature than  either  of  the  metals,  acts  as  a  solder,  to 
unite  them  together.  The  ingot  is  then  rolled  into  sheets, 
by  passing  it,  repeatedly,  between  iron  rollers,  annealing 
it,  from  time  to  time,  as  it  becomes  hard  and  brittle. 

The  plated  sheets,  which  are  thus  obtained,  are  form- 
ed into  articles  of  different  kinds,  by  hammering  them  in 
moulds,  corresponding  to  the  intended  shape.  When 
vessels  are  to  be  made,  they  are  formed  in  pieces  of  a 
convenient  shape,  and  these  are  soldered  together,  with 
an  alloy  of  silver,  copper,  and  brass.  Mouldings,  and 
other  ornamental  parts,  are  made  by  hammering  the  met- 
al in  steel  dies,  or  rolling  it  between  steel  rollers,  upon 
which  the  pattern  is  cut.  As  the  edges  of  plated  ware 
are  most  hable  to  be  injured  by  wear,  they  are  common- 
ly protected  by  what  are  called  silver  edges.  These  are 
19* 


222  ARTS   OF  METALLURGY. 

formed  of  a  shell  of  silver,  rolled  out,  or  hammered  m 
dies,  and  having  its  inside  filled  up  with  a  mixture  of  tin 
and  lead.  When  finished,  these  edges  are  soldered  to 
the  vessel.  The  handles,  feet,  and  solid  parts,  of  vessels 
are  often  made  in  the  same  way.  Plated  baskets,  and 
other  light  articles,  are  made  from  copper  cyhnders,  cov- 
ered with  silver,  and  afterwards  drawn  into  wire. 

Plating  on  iron,  as  it  is  used  for  the  buckles  of  har- 
nesses, and  other  ornaments,  is  executed,  by  first  covering 
the  iron  with  a  coating  of  tin,  and  then  applying,  closely 
to  the  surface,  a  thin  plate  of  silver.  The  union  is  effect- 
ed by  a  moderate  heat,  suflicient  to  melt  the  tin,  and  form 
an  alloy  ;  and  it  is  aided  by  the  use  of  a  resinous  flux. 

COPPER. 

Extraction. — The  various  sulphurets  of  copper  are 
the  most  abundant  of  its  ores  ;  and  of  these,  the  most  so 
is  copper  pyrites.  The  malachite,  red  copper  ore,  and 
others,  are  generally  associated  with  these,  in  small  quan- 
tities. Copper  mines  are  wrought  in  many  countries, 
but  those  of  Sweden  are  said  to  furnish  the  purest  cop- 
per of  commerce.  The  sulphurets  are  the  ores  from 
which  copper  is  usually  extracted.  The  ore  is  roasted 
by  a  low  heat,  in  a  furnace,  with  which  flues  are  connec- 
ted, in  which  the  sulphur,  that  is  volatilized,  is  collected. 
The  remaining  ore  is  then  smelted,  in  contact,  with  the 
fuel.  The  iron  present  in  the  ore,  not  being  so  easily 
reduced,  or  fused,  as  the  copper,  remains  in  the  scoria, 
while  the  copper  is  run  out.  It  often  requires  repeated 
fusions  ;  and,  even  after  these,  it  may  be  still  alloyed  with 
portions  of  metals,  which  are  not  volatile,  and  are  of 
easy  fusion.  Hence,  the  copper  of  commerce  is  never 
altogether  pure,  but  generally  contains  a  little  lead,  and 
a  smaller  portion  of  antimony. 

The  carbonates  of  copper,  reduced  by  fusion,  in  con- 
tact with  the  fuel,  afford  a  purer  copper,  as  does  also  the 
solution  of  sulphate  of  copper,  which  is  met  with  in  some 
mines,  the  copper  being  precipitated  in  its  metalhc  state, 
by  immersing  iron  in  the  solution.  The  precipitate,  which 
is  thus  formed,  is  afterwards  fused. 


WORKING. BRASS.  223 

fVorking. — Copper,  being  ductile  and  easily  wrought, 
IS  applied  to  many  useful  purposes.  It  is  formed  into 
thin  sheets,  by  being  heated  in  a  furnace,  and  subjected 
to  pressure  between  iron  rollers.  These  sheets,  being 
both  ductile  and  durable,  are  applied  to  a  variety  of  uses, 
such  as  the  sheathing  of  the  bottoms  of  ships,  the  cover- 
ings of  roofs  and  domes,  the  constructing  of  boilers  and 
stills,  of  a  large  size,  &c.  Copper  is  also  fabricated 
into  a  variety  of  household  utensils,  the  use  of  which, 
however,  for  preparing  or  preserving  articles  of  food,  is 
by  no  means  free  from  danger,  on  account  of  the  oxidize- 
ment,  to  which  copper  is  liable.  It  has  been  attempted 
to  obviate  this  danger,  by  tinning  the  copper,  or  apply- 
ing to  its  surface  a  thin  covering  of  tin.  This  method 
answers  the  purpose,  as  long  as  the  coating  of  tin  re- 
mains entire. 

Copper  may  be  forged  into  any  shape,  but  will  not  bear 
more  than  a  red  heat,  and,  of  course,  requires  to  be  heat- 
ed often.  The  bottoms  of  large  boilers  are  frequently 
forged  with  a  large  hammer,  worked  by  machinery.  The 
bolts  oi  copper,  used  for  ships,  and  other  purposes,  are 
either  made  by  the  hammer,  or  cast  into  shapes,  and 
roFed.  The  copper  cylinders,  used  in  calico  printing, 
are  either  cast  sohd,  upon  an  iron  axis,  or  are  cast  hollow, 
and  fitted  upon  the  axis.  The  whole  is  afterwards  turn 
ed,  to  render  the  surface  true. 

BRASS. 

Brass  is  an  alloy  of  copper  and  zinc.  The  propor- 
ons  of  these  two  metals  differ,  in  almost  every  place 
n  which  brass  is  manufactured  :  and  the  proportion  of 
zinc  is  found,  in  different  specimens,  to  vary  from  twelve 
to  twenty-five  parts,  in  a  hundred.  The  alloy  is  com- 
nonly  made  from  the  ores  of  zinc  mixed  with  copper, 
and  with  a  sufficient  quantity  of  charcoal,  to  reduce 
them  to  a  metallic  state.  The  volatihty  of  the  zinc  gives 
it  a  tendency  to  escape  in  vapor,  on  which  account,  the 
combination  is  effected  at  a  lower  heat,  than  that  which 
would  be  necessary  to  melt  the  copper.  Several  other 
alloys,  of  the  same  metals,  are  also  known  in  the  arts,  dif- 


224  ARTS   OF  METALLURGY. 

fering  in  the  proportions  of  the  ingredients  ;  such  as  pinch 
beckj  prince' s-metal^  tombac^  Bath-metal^  &c. 

Manufacture. — The  value  of  brass,  in  the  arts,  con- 
sists, in  its  bright  color,  in  its  being  more  fusible  than 
copper,  and  in  its  being  more  easily  wrought  with  com- 
mon tools.  In  the  working  of  brass,  the  larger  articles, 
as  well  as  those  of  comphcated  forms,  are  cast  in  moulds. 
When  it  is  intended,  for  economy  of  the  metal,  that  the 
aiticle  shall  be  hollow,  as  in  the  case  of  andirons,  &c., 
it  is  cast  in  halves,  or  pieces,  which  are  afterwards  sol- 
dered together,  and  turned  in  a  lathe,  or  otherwise  pol- 
ished. Brass  is  also  rolled  into  thin  sheets,  and  drawn 
into  wire.  A  variety  of  figured  and  ornamental  articles 
are  made,  by  stamping  it  in  dies,  or  moulds.  Brass 
knobs  and  similar  implements,  if  large,  are  made  in  pieces, 
and  soldered.  The  wheel-work  of  time-pieces,  and  of 
other  machinery,  which  is  not  subjected  to  great  strain  or 
wear,  is  usually  made  of  brass.  The  comparative  softness 
of  this  alloy  permits  it  to  be  cut  with  thin  saws,  and  to  be 
turned  in  a  lathe,  with  much  greater  ease  than  iron. 

Buttons  are  either  struck  out  of  sheets  of  brass,  with 
a  circular  punch,  driven  by  a  fly-press,  or  they  are  cast, 
in  large  numbers  at  once,  in  a  mould,  or  flask  of  sana. 
The  e?/e,  or  shank,  of  the  button,  is  made  separately,  by 
a  machine,  and  soldered  on,  if  the  button  has  been  cut 
out  by  the  punoh.  If  the  button  is  cast,  the  eye  is  pre- 
viously placed  in  the  mould,  so  that  its  extremity  is  im- 
marsed  in  the  centre  of  the  melted  metal.  If  the  button 
is  to  be  plain,  its  surface  is  planished  by  the  stroke  of  a 
smooth  die  ;  and,  if  figured,  it  is  stamped  with  an  en 
graved  die.  The  edges  are  afterwards  turned  off,  in  a 
lathe.  The  gilding  of  brass  buttons  is  performed,  by  cov- 
ering them  with  an  amalgam  of  gold  and  mercury,  fro... 
which  the  mercury  escapes,  when  heated,  and  leaves  the 
gold.  White-metal  buttons  are  made  of  an  alloy  of  brass 
and  tin,  and  subsequently  coated  with  tin.  The  brass 
eyes  of  pearl  buttons  are  inserted,  by  drilling  a  conical 
hole,  which  is  largest  on  the  inside,  in  the  mother  of 
pearl,  or  shell,  of  which  the  button  is  made.  The  eye, 
naving  an  extremity  like  a  hollow  cone,  is  then  driven  in, 
till  it  spreads,  and  fills  the  cavity. 


PINS. BRONZE.  225 

Pins  are  made  of  brass  wire,  cut  into  proper  lengths. 
The  pieces  are  pointed,  by  turning  them  with  the  fingers, 
upon  stones  or  steel  mills.  The  heads  are  cut  from  a 
spiral  coil  of  wire,  in  pieces  of  a  suitable  length  ;  and,  af- 
ter being  placed  upon  the  pins,  are  shaped  and  fastened, 
by  the  stroke  of  an  instrument  like  a  hammer.  Several 
machines  have  been  invented  for  this  manufacture,  one  of 
which  makes  a  solid  head,  from  the  body  of  the  pin  itself. 
Pins  are  whitened,  by  immersing  them  in  a  vessel,  con- 
taining tin  and  lees  of  wine,  and  are  polished,  by  agita- 
ting them  with  bran,  in  a  revolving  cask. 

Bronze. — A  series  of  alloys  is  formed,  from  the  com- 
bination of  copper  with  tin.  The  combination  appears 
to  have  a  tendency  to  form  in  certain  proportions,  regulat- 
ed, in  some  measure,  by  the  specific  gravities  and  fusibil- 
ities of  the  metals  ;  for,  when  kept  in  fusion,  and  allowed 
to  cool  without  agitation,  two  alloys  are  formed,  the  under 
part  of  the  mass  being  one  of  copper,  with  a  small  portion 
of  tin,  and  the  upper  part  tin,  with  a  small  proportion  of 
copper,  while,  between  these,  there  is,  probably,  a  grada- 
tion. By  agitation,  this  separation  is  counteracted.  In 
general,  tin  lessens  the  ductility  of  copper,  while  it  ren- 
ders it  more  hard,  rigid,  and  sonorous  ;  these  qualities 
being  possessed,  in  various  degrees,  by  the  different  alloys, 
according  to  their  proportions  ;  the  hardness  and  brittle- 
ness  being  greater,  as  the  tin  predominates.  The  densi- 
ty of  the  compound  is,  also,  always  greater  than  the  mean 
density  ;  the  contraction,  from  the  combination,  being 
about  one  eighth.  The  principal  of  these  alloys  are  bronze, 
gun-metal,  from  which  pieces  of  artillery  are  cast,  bell- 
■metal,  and  speculum-metal,  which  has  been  used  for  the 
mirrors  of  reflecting  telescopes.  Bronze  is  one  of  those, 
in  which  the  proportion  of  tin  is  least,. not  exceeding  ten 
or  twelve  parts  in  one  hundred.  It  is  of  a  grayish  yellow 
color,  harder  than  copper,  less  liable  to  rust,  and  more 
fusible,  so  as  to  be  easily  cast  in  moulds.  Hence  it  is 
employed  in  the  casting  of  statues.  The  metal,  from 
which  pieces  of  artillery  are  cast,  is  of  a  similar  compo- 
sition, containing  rather  less  tin.  It  appears  that  an  al- 
loy, very  similar  to  bronze,  was  much  in  use  among  the 


226  ARTS   OF  METALLURGY. 

ancients  ;  and  swords,  darts,  and  other  warlike  instru- 
ments, were  formed  of  it,  as  were  also  various  utensils.* 

When  the  proportion  of  tin  is  increased,  the  alloy  is 
rendered  more  brittle  and  elastic,  and,  at  the  same  time, 
highly  sonorous.  Bell-metal  is  an  alloy  of  this  kind,  in 
which  the  proportion  of  tin  varies  from  one  third  to  one 
fifth  of  the  weight  of  the  copper,  according  to  the  size  of 
the  bell,  and  the  sound  required. 

When  the  proportion  of  tin  is  still  greater,  an  alloy  is 
formed,  called  speculum-metal ,  which  is  of  a  white  color, 
and  which,  from  the  closeness  of  its  texture,  and  its  sus- 
ceptibility of  a  fine  polish,  exceeds  most  metals  in  the 
property  of  reflecting  light.  Hence  it  is  used  in  forming 
the  speculum  of  reflecting  telescopes.  It  has,  also,  the 
advantage  of  not  being  liable  to  tarnish,  on  exposure  to 
the  air.  The  proportion  in  which  these  quahties  w^ere 
best  attained,  appeared,  from  the  experiments  of  Mr. 
Mudge,  to  be  a  little  less  than  one  part  of  tin,  with  two 
parts  of  copper.  The  Chinese  pakfong^  or  white  cop- 
per, which  is  sometimes  imported  from  that  country,  is 
an  alloy,  according  to  Dr.  Fyfe,  of  copper,  zinc,  nickel, 
and  iron.  The  article  used  in  this  country,  and  in  Europe, 
under  the  name  of  German  silver^  is  essentially  an  alloy 
of  copper,  zinc,  and  nickel. 

LEAD. 

Extraction. — Lead,  mineralized  by  sulphur,  forms  by 
far  the  most  abundant  ore  of  the  metal,  and  has  been  long 
known  to  mineralogists  by  the  name  of  galena.  This  is 
the  ore  which  is  generally  wrought,  and  from  which  nearly 

*  According  to  Dr.  Pearson's  experiments,  made  on  various  instru- 
ments of  this  kind,  the  alloy  appears  to  have  consisted  of  about  eight 
or  nine  parts  of  copper,  with  one  of  tin  ;  and,  as  he  justly  remarks, 
this  alloy  still  affords  the  best  substitute  for  iron  or  steel.  While  the 
art,  therefore,  of  manufacturing  malleable  iron  was  imperfectly  known, 
and  difficult  to  be  practised,  it  must  have  been  much  used.  The  hard- 
ness of  this  alloy,  observed  in  ancient  arms,  had  even  given  rise  to  an 
opinion,  that  the  ancients  were  acquainted  with  a  method  of  hardening 
copper,  which  had  been  lost.  Of  this  alloy,  medals  and  coins  were 
also  often  formed,  as  appears  from  the  experiments  of  Dize,  on  sever- 
al Greek,  Roman,  and  CJallic  coins,  which  c?)nsisted  of  copper  and  tin 
alone. 


SHEET-LEAD. LEAL-   PIPES.  227 

all  the  lead  of  commerce  is  procured.  The  ore,  after 
being  pounded,  and  freed  from  the  admixture  of  any  stony 
matter,  by  washing,  is  fused  in  a  furnace,  with  the  addi- 
tion of  lime,  which  combines  with  the  sulphur  of  the  sul- 
phuret  ;  the  lead  is  melted,  and  run  out  by  an  aperture, 
towards  the  bottom  of  the  furnace.  When  the  native  salts 
of  lead  are  found  with  the  galena,  so  as  to  render  it  of 
in..portance  to  work  them,  they  are  selected,  until  a  suffi- 
cient quantity  be  obtained.  They  are  then  roasted,  to 
expel  the  volatile  matter,  and  are  afterwards  fused,  in  con- 
tact with  the  fuel,  with  an  addition  of  lime.  The  lead  ob- 
tained from  galena,  sometimes  contains  so  much  silver,  as 
to  be  subjected  to  an  additional  process  to  separate  the 
silver.  In  this  case,  the  lead  is  oxidized  in  a  furnace ; 
a  current  of  air  being  directed  on  its  surface,  when  in  fu- 
sion, by  bellows.  Towards  the  end  of  the  operation,  the 
silver  remains,  with  a  small  portion  of  lead,  from  which 
it  is  freed,  by  cupellation  ;  and  the  oxide  of  lead  is  either 
applied  to  the  purposes  for  which  it  is  used,  or  is  reduced 
to  the  metallic  state. 

Manufacture. — Lead,  being  fusible  at  a  low  tempera- 
ture, requires  only  to  be  cast  in  smooth  moulds,  to  form 
weights,  bullets,  and  other  articles  of  small  size.  The 
linings  of  cisterns,  and  the  coverings  of  roofs,  gutters, 
&c.,  are  made  of  sheet-lead  ;  pumps,  and  aqueducts,  of 
leaden  pipes. 

Sheet  Lead,  of  the  thicker  kinds,  is  cast  upon  large 
tables,  covered  with  sand,  and  having  an  elevated  rim. 
The  melted  lead  is  poured  upon  the  surface,  out  of  a  box, 
which  moves  upon  rollers  across  the  table,  and  is  spread 
out  with  a  uniform  thickness,  by  passing  over  it  a  straight 
piece  of  wood,  called  a  strike.  The  sheets,  thus  cast, 
are  afterwards  rendered  thinner,  by  reducing  them  between 
rollers.  The  sheet-lead  with  which  tea-chests  are  lined, 
is  an  alloy  of  lead  and  tin,  and  is  made  by  the  Chmese, 
by  suddenly  compressing  the  melted  metal  between  flat, 
polished  stones. 

Lead  pipes,  for  conveying  water,  may  be  made  in  vari- 
ous ways.  They  were  at  first  formed  of  sheet  lead,  bent 
round  a  cylindrical  bar,  or  mandrel,  and  soldered  ;  but 


228  ARTS   OF  METALLURGY. 

these  pipes  are  liable  to  crack  and  leak,  especially  when 
bent.  A  second  method  is,  to  cast  a  short  tube  of  lead 
in  a  cylindrical  mould,  with  a  core.  This  tube,  when 
cold,  is  drawn  nearly  out  of  the  mould,  and  a  fresh  por- 
tion of  melted  lead  poured  in,  at  apertures  in  the  sides 
of  the  mould.  The  melted  lead  unites  with  the  tube, 
])reviously  formed,  so  as  to  increase  its  length ;  and  by 
repeating  the  process,  any  length  of  pipe  may  be  pro- 
duced. But  pipes,  cast  in  this  manner,  are  found  to  have 
imperfections,  arising  from  flaws  and  air  bubbles.  A 
third  method,  which  is  now  most  commonly  practised,  is 
to  cast  a  short,  thick  tube  of  lead,  upon  one  end  of  a 
long,  polished,  iron  cylinder,  or  mandrel,  gf  the  size  of 
the  bore  of  the  intended  pipe.  The  lead  is  then  reduced 
in  size,  and  drawn  out  in  length,  either  by  drawing  it  on 
the  mandrel,  through  circular  holes,  of  different  sizes,  in 
a  steel  plate  ;  or  by  rolling  it  between  contiguous  rollers, 
which  have  a  semi-circular  groove,  cut  round  the  circum- 
ference of  each.  A  fourth  mode,  invented  by  Mr.  Bra- 
mah,  consisted  in  forcing  melted  lead,  by  means  of  a 
pump,  into  one  end  of  a  mould  ;  while  it  was  discharged, 
in  the  form  of  a  pipe,  at  the  opposite  end.  'Care  was 
taken,  so  to  regulate  the  temperature,  that  the  lead  should 
chill,  just  before  it  left  the  mould. 

Leaden  shot  consist  of  drops  of  metal,  which  are  dis- 
charged, in  a  melted  slate,  from  small  orifices,  and  cool 
in  falling.  The  best  shot  are  cast  in  high  towers,  built 
for  the  purpose.  The  lead  is  previously  alloyed  with  a 
portion  of  arsenic,  which  increases  the  cohesiveness  of  its 
particles,  and  causes  it  to  assume,  more  readily,  the  glob 
ular  form.  It  is  melted,  at  the  top  of  the  tower,  and 
poured  into  a  vessel,  which  is  perforated  at  bottom,  with 
numerous  small  holes.  The  lead,  after  running  through 
these  perforations,  immediately  separates  into  drops,  which 
cool,  in  falling  through  the  height  of  the  tower,  and  are 
received  in  a  reservoir  of  water,  at  bottom,  to  break  the 
force  of  the  fall.  The  shot  are  then  proved,  by  rolling 
them  down  an  inclined  board.  Those  which  are  irregulai 
m  shape  roll  off  at  the  sides,  or  stop,  while  the  spherical 
ones  continue  to  the  end.     They  are  then  assorted,  by 


TIN. BLOCK  TIN. TIN  PLATES.  229 

passing  them  through  wire  sieves  of  different  fineness. 
The  glazing  is  given,  by  agitating  them  with  small  quan- 
tities of  black  lead. 

Shot  is  sometimes  made,  mechanically,  by  cutting  sheets 
of  lead  into  cubes,  and  agitating  these,  for  a  long  time,  in 
a  cylindrical  vessel,  turned  upon  an  axis.  The  attrition, 
thus  produced,  communicates  a  globular  form  to  the  cubes. 

TIN. 

Native  oxide  of  tin,  or  tinstone^  as  it  is  commonly  nam- 
ed, is  the  only  ore  that  is  wrought,  to  obtain  this  metal. 
Being  freed,  by  washing,  from  the  intermixture  of  any 
stony  matter,  it  is  roasted,  and  then  fused,  in  contact  with 
the  fuel,  by  a  moderate  heat.  The  tin  of  Cornwall  is 
supposed  to  be  purer  than  the  German  tin,  though  it  is 
still  inferior  to  the  tin  from  India. 

Block-tin^  consisting  of  the  metal  in  its  solid  state,  is 
used  for  vessels  which  are  not  exposed  to  a  temperature 
much  exceeding  that  of  boiling  water.     Vessels  of  this 
kind,  being  not  readily  tarnished,  form  a  cheaper  substi- 
tute for  silver  and  plated  ware.      A  kind  of  ware,  de- 
nominated Biddery  ware,  consists  of  tin  vessels,  alloyed 
with  a  litde  copper,  and  having  their  surface  made  black 
by  the  application  of  substances,  containing  nitre,  com 
mon  salt,  with  sal  ammoniac.      Tin-foil  is  made  by  rol 
ling,  in  the  same  way  as  the  plates  for  tinned  iron  here- 
after described.     It  is  also  sometimes  hammered.     The 
most  extensive  use,  however,  to  which  metalhc  tin  is  ap- 
pHed,  is  to  form  a  coating  for  other  metals,  which  are 
stronger  than  itself,  but  at  the  same  time  more  liable  to 
oxidation  by  exposure  to  the  air. 

Tin  plates,  which  constitute  the  material  of  the  com- 
mon  tin  ware,  so  extensively  used,  are  thin  sheets  of  iron, 
coated  with  tin.  The  mode  of  rolling  these  sheets  wil] 
be  described  under  the  head  of  Iron.  To  prepare  them 
for  tinning,  they  are  steeped  in  water,  acidulated  with 
muriatic  acid,  and  then  heated,  scaled,  and  rolled,  to  re- 
move all  oxide,  and  enable  the  tin  to  adhere  to  the  iron. 
The  (in  is  kept  melted  in  oblong,  rectangular  vessels,  and 
to  preserve  its  surface  from  oxidation,  a  quantity  of  melt- 
II.  20  XII. 


230  ARTS   OF  METALLURGY. 

ed  fat  and  oil  is  kept  floating  upon  it.  The  iron  plates 
are  taken  up  with  pincers,  and  immersed  in  the  tin  for 
some  time.  When  withdrawn,  they  are  found  to  have 
acquired  a  bright  coating  of  the  tin,  which  adheres  closely, 
owing  to  the  formation  of  an  intermediate  alloy.  The 
dipping  is  repeated  twice,  or  more  times,  according  to 
the  thickness  of  the  coat  intended  to  be  given,  and  also  to 
produce  a  smooth  surface,  and,  between  these  processes, 
the  tin  is  equahzed  with  a  brush.* 

Various  other  articles  of  iron,  such  as  spoons,  nails, 
bridle-bits,  small  chains,  &ic.  are  coated  with  tin,  by  im- 
mersing them  in  that  metal,  while  in  a  state  of  fusion. 
From  the  affinity  between  tin  and  copper,  a  thin  layer  of 
the  former  metal  can  be  easily  applied  to  the  surface  of 
the  latter  ;  and  this  practice  of  tinning,  as  it  is  named,  is 
often  employed,  to  prevent  the  erosion,  or  rusting,  of 
copper  vessels,  and  the  noxious  impregnation  which  they 
would  otherwise  communicate  to  liquors  kept  in  them. 
The  surface  of  the  copper  is  polished,  so  as  to  be  quite 
bright  ;  sal-ammoniac  is  applied  to  it,  when  hot,  by  which 
the  oxidation  appears  to  be  prevented  ;  or  pitch  is  some- 
times used,  for  the  same  purpose.  The  melted  tin,  or, 
sometimes,  an  alloy  of  tin  and  lead,  is  then  applied  to  the 
surface  of  the  copper,  to  which  it  readily  adheres. 

Silvering  of  Mirrors. — The  surfaces,  best  adapted  for 
reflecting  light,  are  those  of  polished  metals.  To  con- 
stitute a  good  reflector,  it  is  necessary  that  a  metal  should 
be  susceptible  of  an  equal,  unbroken,  and  exquisite,  pol- 
ish, and  that  it  should  retain  this  polish,  without  being 
tarnished  by  the  atmosphere.  Speculum-metal  is,  chiefly, 
employed  for  reflecting  surfaces,  in  telescopes  ;  but,  for 
common  purposes,  an  amalgam  of  tin  and  mercury  is  used, 
m  a  state  of  adhesion  to  glass.  The  use  of  the  glass  is, 
in  the  first  place,  to  produce  a  smooth  surface,  in  the 
amalgam  ;  and,  afterwards,  to  protect  it  from  oxidation  by 
the  atmosphere. 

In  the  silvering  of  plain  looking-glasses,  a  flat,  hori- 

*  For  a  full  account  of  tho  present  mode  of  manufacturing  tin  plate, 
gee  Parkes's  Chemical  Essays,  vol.  ii. 


IRON.  231 

tontal  slab  of  stone  is  used,  as  a  table.  Phis  is  smoothly 
covered  with  paper,  and  a  sheet  of  tin-foil,  equal  to  the 
size  of  the  glass,  is  extended  over  it.  A  quantity  of 
mercury  is  then  laid  upon  the  tin-foil,  and  immediately 
spread  over  it,  with  a  roll  of  cloth,  or  a  hare's  foot.  Af- 
terwards, as  much  mercury,  as  the  surface  will  hold,  is 
poured  on.  While  this  mercury  is  yet  in  a  fluid  state, 
the  plate  of  glass  is  slid  on,  at  the  edge  of  the  table,  so  as 
to  pass  over  the  tin-foil,  driving  the  superfluous  mercury 
before  it.  In  this  way,  any  bubbles  of  air  and  particles 
of  dust  are  prevented  from  getting  between  the  glass  and 
the  metal,  and  an  uninterrupted  coating  is  formed.  In 
order  to  force  out  the  remaining  liquid  mercury,  the  glass 
is  placed  in  a  sloping  position,  to  allow  the  mercury  to 
drain  ofl',  after  which,  heavy  weights  are  placed  upon  the 
glass,  and  suffered  to  remain,  for  some  time.  The  por- 
tion, which  is  left,  amalgamates  with  the  tin,  and  forms  a 
permanent  reflecting  surface,  the  smoothness  and  perfec 
fion  of  which  depend  upon  the  degree  of  regularity  and 
polish,  which  the  glass  possesses. 

In  silvering  concave  and  convex  mirrors,  instead  of 
A  stone  table,  the  tin-foil  is  spread  upon  a  plaster  mould, 
previously  cast  on  the  surface  of  the  glass  hself.  The 
inside  of  glass  globes  is  silvered,  by  pouring  into  them  a 
fusible  alloy  of  tin,  lead,  bismuth,  and  mercury,  the  heat 
of  which,  when  liquid,  is  not  sufficient  to  break  the  glass 
By  turning  the  globe  about,  a  thin  metallic  coating  is  de- 
posited on  the  whole  interior  surface. 

IRON. 

The  properties  which  iron  possesses,  in  its  various 
forms,  render  it  the  most  useful  of  all  the  metals.  The 
toughness  of  malleable  iron  adapts  it  to  purposes,  where 
great  strength  is  required  ;  while  its  combination  of  diffi- 
cult fusibility  with  the  property  of  softening  by  heat,  so 
as  to  admit  of  forging  and  welding,  renders  it  capable  of 
being  easily  worked,  and  of  withstanding  an  intense  heat. 
Cast-iron,  from  its  cheapness,  and  the  facility  with  which 
Jts  form  is  changed  by  fusion,  is  made  the  material  of 
numerous  structures  and  machines.      Steel,  which  is  the 


232  ARTS   OF  METALLURGY. 

most  important  compound  of  iron,  exceeds  all  other  me- 
tals, in  the  combination  of  hardness  and  tenacity ;  and 
hence,  it  is  particularly  adapted  to  the  fabrication  of  cut- 
ting instruments.  It  is  equally  superior  in  elasticity,  a 
quality  by  which  it  is  suited  to  be  the  spring  of  motion, 
in  various  machines. 

Smelting. — The  principal  ores,  which  are  wrought  for 
the  extraction  of  iron,  are  the  different  species  of  the  na- 
tive oxides.  The  process  is  somewhat  different,  as  car- 
ried on,  in  different  countries,  and  as  adapted  to  different 
ores  ;  but  the  following  is  the  general  outline  of  it,  as  it 
is  conducted  on  the  haematite  bog-ores,  and  other  oxides 
of  iron. 

The  blast-furnace,  in  which  the  operation  is  conducted, 
is  a  large  pyramidal  stack,  made  of  brick  or  hewn  stone, 
from  twenty  to  sixty  feet  high,  having  its  internal  cavity 
shaped  like  an  egg,  with  its  large  end  downwards,  and 
lined  with  fire-brick  or  stone. 

The  ore  is  first  roasted,  with  a  strong  heat,  to  expel 
the  carbonic  acid,  and  any  portion  of  sulphur,  or  other 
volatile  matter,  that  may  be  present.  The  remaining  ore 
is  put  into  a  furnace,  of  a  conical  form,  with  charcoal,  or 
with  coke,  and  exposed  to  a  heat,  rendered  sufficiently 
intense  by  a  blast  of  air,  urged  through  the  furnace.  A 
quantity  of  lime  is,  at  the  same  time,  added  to  the  ore 
and  fuel ;  the  advantage  of  which  appears  to  be,  that  in 
combination  with  the  argillaceous  and  sihcious  substances, 
generally  contained  in  the  iron  ores,  it  acts  as  a  flux,  to 
vitrify  the  foreign  matter,  and  thus  facilitate  the  separation 
of  the  melted  metal.  The  proportions  of  these  are  ex- 
tremely various,  according  to  the  nature  of  the  ore.  When 
the  furnace  is  once  charged,  the  charge  is  renewed  at 
the  upper  part,  as  fast  as  the  materials  sink,  and  the  pro- 
cess is  carried  on,  for  a  long  time,  without  interruption. 
During  this  process,  the  oxygen  of  the  oxide  of  iron  unites 
with  one  portion  of  the  carbon,  and  the  metal  with  anoth- 
er, producing  carbonic  acid,  and  carburet  of  iron  ;  while 
the  earthy  substances,  together  with  a  little  oxide  of  iron, 
enter  into  combination,  forming  a  vitreous  substance  call- 
ed slag,  or  scoria,  and  which,  being  lighter  than  the  me 


CRUDE   IRON. CASTING.  233 

tal,  rises  upon  its  surface.  The  slag  is  drawn  oiF,  by  an 
opening,  and  the  melted  metal  is  collected  in  a  cavity,  at 
bottom,  from  which,  as  it  accumulates,  it  is  conveyed  off, 
at  intervals,  into  moulds. 

A  vast  improvement,  in  regard  to  the  saving  of  fuel, 
has  been  produced,  in  late  years,  by  the  introduction  of 
the  hot  blast,  in  smelting  furnaces.  The  fire,  in  this  case, 
is  blown  by  air,  previously  heated  ;  the  combustion  be- 
comes more  effective  ;  and  a  saving  of  tw^o  thirds  of  the 
fuel  is  said  to  be  produced. 

Crude  Iron, — The  metal  thus  obtained,  is  named  pig- 
iron,  and  crude,  or  cast-iron.  It  is  far  from  being  pure, 
containing,  always,  more  or  less  oxygen  and  carbon  ;  and, 
often,  several  other  heterogeneous  ingredients,  such  as 
manganese,  and  the  metaUic  bases  of  lime,  clay,  and  silex, 
with  portions  of  unreduced  ore  and  charcoal.  The  oxy- 
gen is,  partly,  a  portion  of  what  was  originally  combined 
with  the  metal,  in  the  ore,  and  partly,  perhaps,  derived 
from  the  blast  of  air,  which  is  driven  through  the  furnace, 
and  necessarily  presented  to  the  metal,  in  a  state  of  fusion 
Hence,  the  qualities  of  cast-iron  are  very  various,  accord 
ing  as  one  or  other  of  the  principles  predominates. 

Iron,  in  this  state,  is  readily  capable  of  being  fused, 
and  cast  into  moulds.  It  is,  however,  much  more  brittle, 
than  w^hen  pure,  and  cannot  be  wrought  or  flattened,  un- 
der the  hammer.  Hence,  it  is  altogether  unfit  for  many 
purposes,  to  which  pure  or  malleable  iron  is,  from  its  te- 
nacity and  softness,  w^ell  adapted. 

Casting. — Iron,  as  well  as  brass,  and  other  metals, 
which  melt  at  temperatures  above  ignition,  is  cast  in 
moulds,  made  of  sand.  The  kind  of  sand,  most  employ 
ed,  is  loam,  which  possesses  a  sufficient  portion  of  argil- 
laceous matter,  to  render  it  moderately  cohesive,  when 
damp.  The  mould  is  formed,  by  buryniti,  in  the  sand,  a 
wooden  pattern,  having  exactly  the  shape  of  the  article 
to  be  cast.  The  sand  is  most  commonly  enclosed  in 
flasks,  which  are  square  frames,  resembling  wooden  box- 
es, open  at  top  and  bottom.  If  the  pattern  be  of  such 
form,  that  it  can  be  lifted  out  of  the  sand,  without  derang- 
ing the  form  of  the  mould,  it  is  only  necessary  to  make 
20* 


234  ARTS   OF  METALLURGY. 

an  impression  of  the  pattern,  in  one  flask.;  and  articles 
of  this  kind  are  sometimes  cast  in  the  open  sand,  upon 
the  floor  of  the  foundry.  But  when  the  shape  is  such, 
that  the  pattern  could  not  be  extracted,  without  breaking 
the  mould,  two  flasks  are  necessary,  having  half  the  mould 
formed  in  each.  The  first  flask  is  filled  with  sand,  by 
ramming  it  close,  and  is  smoothed  ofl*,  at  the  top.  The 
pattern  is  separated  into  halves,  one  half  being  imbedded 
m  this  flask.  A  quantity  of  white  sand,  or  burnt  sand, 
IS  sprinkled  over  the  surface,  to  prevent  the  two  flasks 
from  cohering.  The  second  flask  is  then  placed  upon 
the  top  of  the  first,  having  pins  to  guide  it.  The  other 
half  of  the  pattern  is  put  in  its  place,  and  the  flask  is  filled 
with  sand,  which,  of  course,  receives  the  impression  of 
the  remaining  half  of  the  pattern,  on  its  under  side.  After 
one  or  more  holes  are  made  in  the  top,  to  permit  the  met- 
al to  be  poured  in,  and  the  steam  and  air  to  escape,  the 
flasks  are  separated,  and  the  pattern  withdrawn.  When 
the  flasks  are  again  united,  a  perfect  cavity,  or  mould,  is 
formed,  into  which  the  melted  metal  is  poured. 

The  arrangement  of  the  mould  is,  of  course,  varied, 
for  different  articles.  When  the  form  of  the  article  is 
complex  and  diflicult,  as  in  some  hollow  vessels,  crooked 
pipes,  &c.,  the  pattern  is  made  in  three  or  more  pieces, 
which  are  put  together,  to  form  the  moulds,  and  after- 
wards taken  apart,  to  extract  them.  In  some  other  ir- 
regular articles,  as  andirons,  one  part  is  cast  first,  and 
afterwards  inserted  in  the  flask  which  is  to  form  the  other 
part. 

The  metal  for  small  articles  is  usually  dipped  up,  witli 
iron  ladles  coated  with  clay,  and  poured  into  the  moulds. 
In  large  articles,  such  as  cannon,  the  mould  is  formed  in 
a  pit,  dug  in  the  earth,  near  the  furnace,  and  the  melted 
metal  is  conveyed  to  it,  in  a  continued  stream,  through  a 
channel  communicating  with  the  bottom  of  the  furnace. 

Cannon  balls  are  sometimes  cast  in  moulds,  made  of 
iron  ;  and  to  prevent  the  melted  metal  from  adhering,  the 
inside  of  the  mould  is  covered  with  powder  of  black  lead. 
Rollers  for  flattening  iron  are  also  cast  in  iron  cases. 
This;  method  is  called  chill- castings  and  has,  for  its  ob 


MALLEABLE  IRON. FORGING.  235 

ject,  the  hardening  of  the  surface  of  the  metal,  by  the 
sudden  reduction  of  temperature,  which  takes  place  in 
consequence  of  the  superior  conducting  power  of  the  iron 
mould.  These  rollers  are  afterwards  turned  smooth,  in  a 
powerful  lathe,  which  has  a  slow  motion,  that  the  cutting 
tool  may  not  become  heated  by  the  friction. 

Malleable  Iron. — To  obtain  pure  iron,  that  is,  to  free 
crude  iron  from  the  oxygen,  carbon,  and  other  foreign 
substances,  contained  in  it,  it  is  subjected  to  two  opera- 
tions,— melting,  and  forging.  The  fusion  is  performed 
in. difl'erent  furnaces.  The  melted  metal  is,  in  some  cases, 
run  out,  to  free  it  from  the  scoria  which  has  separated  ; 
and  this  process  is  repeated,  until  the  iron  attains  a  degree 
of  consistence,  sufficient  to  be  submitted  to  the  action  of 
the  forge-hammer.  But,  more  commonly,  the  metal  is 
kept  in  fusion,  in  a  reverberatory  furnace,  called  a  pud- 
dling-furnace,  where  it  is  raised  to  a  very  high  tempera- 
tur-e.  The  liquid  is  stirred  frequently,  to  facilitate  the 
combination  of  the  carbon  and  oxygen.  At  length,  a 
lambent  blue  flame  appears  on  its  surface,  probably  from 
the  formation  and  disengagement  of  carbonic  oxide  ;  and, 
after  some  time,  the  fluidity  of  the  metal  diminishes,  until 
it,  at  length,  assumes  the  consistence  of  a  stiff  paste.  It 
IS  then  suDjected  to  the  action  of  a  very  large  hammer, 
or  to  the  more  equable  pressure  of  rollers,  by  which  a 
portioa  of  oxide  of  iron,  carbon,  and  other  heterogeneous 
substances,  not  consumed  during  the  fusion,  are  forced 
out.  The  iron,  in  this  state,  is  no  longer  granular  in  its 
texture,  but  is  soft,  ductile,  and  malleable,  and  much  less 
fusible.  It  is  then  named  wr ought-iron.,  forged.,  or  bar 
iron,  as  it  is  generally  formed  into  long  bars.  A  consid- 
erable loss  of  weight  attends  the  process,  from  the  dissi- 
pation of  the  foreign  substances,  contained  in  the  crude 
iron,  and  from  the  oxidation  of  the  surface  of  the  metal. 
The  operation  is  generally  perform.ed  on  the  varieties 
called  white,  or  gray,  crude  iron. 

Forging. — Forging  consists  in  changing  the  form  of 
iron,  and  other  malleable  metals,  by  percussion,  applied 
to  them,  while  they  are  softened  by  heat.  Iron,  when 
exposed  to  the  action  of  great  heat,  becomes  highly  mal- 


236  ARTS   OF  METALLURGY. 

leable  and  ductile.  It  is  also  capable  of  welding,  at  a 
sufficiently  high  temperature.  Most  other  metals  have 
their  malleabihty  improved,  by  a  certain  degree  of  heat, 
but  become  brittle,  if  the  heat  is  carried  near  to  then-  fu- 
sing point.  The  strength  and  quality  of  iron,  on  the 
contrary,  are  improved,  by  forging  at  a  strong  white  heat, 
since  the  parts  become  consolidated,  and  the  flaws  oblit 
erated,  by  hammering,  at  a  welding  temperature. 

The  joint  action  of  the  heat  and  current  of  air.  used  ii 
forges,  tends  to  oxidate,  rapidly,  the  surface  of  iron.    Th' 
oxide  which  is  formed  has  some  tendency  to  vitrification 
when  combined  w^ith  silicious  matter.     Hence  it  is  a  com 
mon  practice  among  workmen,  to  immerse  the  iron  in  sand . 
when  it  is  near  to  a  welding  heat.      A  vitreous  coating  is, 
by  this  means,  formed,  which  protects  the  surface  of  th  • 
iron  from  further  oxidation.      This  coating  would  prevent 
the  different  pieces  from  uniting,  by  welding,  were  it  not 
that  its  fluidity  causes  it  to  escape,  while  under  the  action 
of  the  hammer. 

The  forging,  at  the  furnaces,  of  large  masses  of  iron, 
called  blooms,  is  performed  by  the  aid  of  tilt-hammers,  as 
is  also  that  of  anchors,  and  various  other  massive  imple- 
ments, and  parts  of  machines.  Bars  of  iron  are  common- 
ly rolled,  and  when  heavier  articles,  such  as  anchors,  are 
to  be  made,  a  sufficient  number  of  bars,  for  the  purpose, 
are  welded  together. 

.  A  tih-hammer,  of  the  kind  used  in  iron-works,  is  shown 
in  PI.  III.,  Fig.  2.  x\B,  is  the  hammer,  which  turns 
upon  the  fulcrum,  C.  At  D,  is  a  wheel,  or  cyhnder, 
furnished  w^ith  wipers,  [abc,  &c.,]  each  of  which,  as  it 
passes,  strikes  the  end.  A,  of  the  helve,  and  causes  the 
liammer-end,  B,  to  rise.  The  hammer  then  desornds, 
with  its  own  weight,  and  is  accelerated  by  the  recoil  of 
the  end.  A,  from  the  fixed  obstacle,  E.  The  wipers 
may  be  indefinitely  varied,  in  number  and  position,  and 
are  sometimes  apphed,  on  the  other  side  of  the  fulcrum. 
The  recoil,  likewise,  is  sometimes  produced  by  a  spring, 
placed  over  the  end,  B,  of  the  hammer.  The  motion 
of  these  engines  is  extremely  rapid,  and  is  commonly  reg 
ulated  by  a  fly-wheel. 


ROLLING  AND   SLITTING.  237 

Rolling  and  Slitting, — Malleable  iron  is  commonly- 
wrought  into  those  shapes  which  have  flat,  parallel  sur- 
faces, by  submitting  it  to  compression,  between  rollers. 
Bars,  plates,  and  sheets,  of  iron  are  formed,  in  this  way. 
A  pair  of  heavy  cylindrical  rollers,  made  of  iron,  chill- 
cast,  and  turned  snwoth,  are  connected  together  by  strong 
iron  bearings,  a  space  being  left  between  them,  equal  to 
the  intended  thickness  of  the  metal,  which  is  to  be  rolled. 
This  distance  is  varied,  by  adjusting  it  with  powerful 
screws.  The  iron,  which  is  to  be  rolled,  is  prepared, 
by  heating  it  red  hot,  and,  in  this  state,  it  is  presented  to 
the  rollers.  As  soon  as  any  part  has  entered,  so  as  to 
fill  the  space  between  the  rollers,  the  friction,  or  adhesion, 
becomes  sufficient  to  draw  in  the  remainder,  in  opposition 
to  the  force  with  which  the  metal  resists  cqmpression. 
The  iron,  in  passing  through,  is  compressed  into  a  uni- 
form plate,  of  equal  thickness,  and  is,  at  the  same  time, 
extended  in  length,  but  is  very  little  increased  in  breadth. 
As  the  rollers  usually  move  with  considerable  velocity, 
the  heated  iron  may  be  passed,  several  times,  between 
different  pairs  of  rollers,  before  it  cools.  To  prevent  the 
rollers  from  becoming  heated,  a  continual  stream  of  water 
is  let  fall  upon  their  surface. 

As  the  principal  extension,  w'hich  plates  receive,  is  in 
I  longitudinal  direction,  it  is  necessary  to  vary  their  po- 
sition, when  it  is  desired  to  increase  their  width.  This  is 
sometimes  done,  by  passing  them  in  an  obhque  direction  ; 
but,  in  making  sheet-iron  and  wide  plates,  it  is  necessary 
to  pass  the  pieces  through  the  rollers,  in  the  direction  of 
their  breadth,  as  well  as  length,  that  they  may  be  extend- 
ed in  both  directions.  Very  thin  plates,  like  those  used 
for  tinned  iron,  are  repeatedly  doubled,  and  passed  be- 
tween the  rollers,  so  that,  in  the  thinnest  plates,  sixteen 
thicknesses  are  rolled,  together,  care  being  taken  to  change 
their  relative  positions,  and  to  interpose  oil,  to  prevent 
them  from  cohering.  The  last  rollings  are  performed, 
while  the  metal  is  cold.  Bars  which  are  square,  round; 
and  of  various  other  shapes,  are  formed,  between  rollers 
which  have  grooves  cut  upon  their  circumferences,  cor- 
responding, in  shape,  to  half  the  bar  to  be  made.     Even 


238  ARTS   OF  MFTALLURGY 

rails  of  malleable  iron,  for  rail-roads,  have  lately  been 
made  between  rollers,  formed  for  the  purpose. .  And,  at 
some  furnaces,  where  malleable  iron  is  made,  the  forge- 
hammer  is  dispensed  with,  and  reliance  is  placed  on  the 
rollers,  alone,  to  consolidate  anc^  equalize  the  masses  of 
metal. 

Slitting  rollers,  or  those  intended  for  dividing  plates 
of  iron  into  narrow  rods,  are  formed  with  elevated  rings 
upon  their  circumferences,  which  reciprocally  enter  be- 
tween each  other,  their  edges  being  angular,  and  passing 
in  close  contact  with  each  other,  so  as  to  cut  like  shears. 
These  rings  are  separately  made,  so  tha*  tbey  can  be  re- 
moved from  the  rollers,  for  the  purpose  of  sharpening 
them,  when  necessary. 

Wire  Drawing. — The  manufacture  of  w^ire  consists,  in 
drawing  a  piece  of  metal  through  a  conical  hole  in  a 
steel  plate,  which  forms  it  into  a  regular  cylindrical  fila- 
ment. The  size  of  this  filament  may  be  reduced,  and 
the  length  extended,  indefinitely,  by  passing  it  through 
successive  holes,  which  gradually  diminish  in  diameter. 

To  prepare  the  iron  for  drawing,  it  is  first  subjected  to 
the  action  of  the  hammer,  till  it  is  reduced  to  a  size  tha* 
will  admit  of  its  being  drawn  through  the  plate.      Some 
times,  the  iron  is  prepared  by  rolling ;  but  the  best  wire  i 
produced,  when  the  metal  has  been  thoroughly  hammered 

The  rod  of  iron  which  has  been  prepared,  in  this  man 
ner,  is  next  drawn  through  one  of  the  larger  holes  in  thi 
steel  plate.     Various  machines  are  employed,  to  over 
come  the  resistance  which  the  plate  opposes  to  the  com 
pression  and  passage  of  the  wire.     In  general,  the  end 
of  the  wire  is  held  by  pincers,  and  as  fast  as  the  wire  is 
drawn  through  the  plate,  it  is  wound  upon  a  roller,  by  the 
action  of  a  wheel  and  axle,  or  other  power.      Sometimes, 
a  rack  and   pinion  is  employed,  for   this  purpose,  and 
sometimes,  a  lever,  which  acts  at  intervals,  and  takes  fresh 
hold  of  the  wire,  each  time  that  the  force  is  applied. 

The  finer  kinds  of  wire  are  made  from  the  larger,  by 
repeated  drawings,  each  of  which  is  performed  through  a 
smaller  hole  than  the  precedin^o'.  As  the  metal  becomes 
stiff  and  hard,  by  the  repetition  of  this  process,  it  is  nee- 


NAIL-MAKING. GUN-MAKING.  239 

essary  to  anneal  it,  from  time  to  time,  to  restore  its  duc- 
tility. It  is  also  occasionally  immersed  in  an  acid  liquid, 
to  loosen  the  superficial  oxide  which  is  formed,  in  the 
process  of  annealing. 

JVai7  Making. — Nails  are  made,  both  by  hand,  and 
by  machinery.  Wrought-nails  are  made,  singly,  at  the 
forge  and  anvil,  by  workmen  who  acquire,  from  practice, 
great  despatch  in  the  operation.  Machines  have  been 
made,  for  making  these  nails  perfectly,  and  with  rapidi- 
ty ;  yet  they  have  not  come  into  general  use,  owing  to 
the  cheapness  of  the  product  "by  manual  labor.  Cut- 
nails  are  made,  almost  wholly,  by  machinery,  invented 
in  this  country.  The  iron,  after  having  been  rolled,  and 
slit  into  rods,  is  flattened  into  plates,  of  the  thickness  in- 
tended for  the  nails,  by  a  second  rolling.  The  end  of 
this  plate  is  then  presented  to  the  nail-machine,  by  a  work- 
man, who  turns  the  plate  over,  once,  f6r  every  nail.  The 
machine  has  a  rapid  reciprocating  motion,  and  cuts  oiT, 
at  every  stroke,  a  wedge-shaped  piece  of  iron,  constitu- 
ting a  nail  without  a  head.  This  is  immediately  caught, 
near  its  largest  end,  and  compressed  between  gripes. 
At  the  same  time  a  strong  force  is  applied  to  a  die,  at  the 
extremity,  which  spreads  the  iron,  sufficiently  to  form  a 
head  to  the  nail.  Some  nails  are  made  of  cast-iron,  but 
these  are  always  brittle,  unless  afterwards  converted  into 
malleable  iron,  by  the  requisite  process. 

Gun  Making. — Cannon,  carronades,  &c.,  whether  of 
iron  or  brass,  are  cast  in  sand,  and  afterwards  bored. 
Muskets  and  fowhng-pieces  are  forged  from  bars  of  mal- 
leable iron.  The  bar  is  first  flattened  by  hammering, 
till  it  attains  the  requisite  width.  It  is  then  made  into  a 
tube,  by  turning  it  over  a  mandrel,  or  cylindrical  rod,  of 
a  size  which  is  smaller  than  that  of  the  intended  bore. 
The  edges  are  made  to  overlap  each  other,  about  half  an 
inch,  and  are  firmly  welded  together.  The  whole  is  then 
consolidated  and  strengthened,  by  hammering  it,  for  some 
time,  in  semi-circular  grooves,  on  a  swage,  or  anvil,  which 
is  furrowed  for  the  purpose.  To  render  the  barrel  smooth, 
on  (he  inside,  and  perfectly  true,  it  is  afterwards  bored 
out,  with  an  instrument  somewhat  larger  than  the  man 


240  ARTS   OF  METALLURGY. 

drel ;  and  several  such  instruments,  of  different  sizes,  ar« 
employed,  in  succession.  The  breech  of  the  barre  is 
closed,  by  a  strong  plug,  which  is  firmly  screwed  in,  at 
the  extremity.  The  projecting  parts  of  the  barrel,  such 
as  the  sight,  and  the  loops  which  confine  it  to  the  stock, 
are  soldered  on.  The  construction  of  the  lock,  and  oth- 
er appendages,  is  readily  understood,  from  inspection. 

Steel. — When  malleable  iron  is  re-combined  with  car- 
bon, in  a  much  smaller  proportion,  it  forms  steel.  Differ- 
ent methods  are  followed,  to  form  this  combination.  The 
product  varies,  according  to  the  method  pursued,  and  is 
also  effected,  by  the  introduction  of  other  substances  into 
the  combination.  The  best  steel  is  made  from  Swedish 
and  Russian  iron. 

The  general  method  of  forming  steel  is,  by  the  process 
of  cementation.  A  furnace  is  constructed,  of  a  conical 
form,  in  which  are  two  large  cases,  or  troughs,  of  fire- 
brick, capable  of  holding  some  tons  of  iron.  Beneath 
these,  is  a  long  grate,  on  which  the  fuel  is  placed.  On 
the  bottom  of  the  case,  is  placed  a  layer  of  charcoal  dust ; 
over  this,  a  layer  of  bars  of  malleable  iron  ;  over  this, 
again,  a  layer  of  charcoal  powder  ;  and  the  series  of 
alternate  layers  of  charcoal  and  iron  is  thus  raised  to  a 
considerable  height.  The  whole  is  covered  with  clay, 
to  exclude  the  air  ;  and  flues  are  carried  through  the  pile 
from  the  furnace,  so  as  to  communicate  the  heat  more 
completely  and  equally.  The  fire  is  kept  up,  for  eight 
or  ten  days.  The  progress  of  the  cementation  is  dis- 
covered, by  withdrawing  a  bar,  called  the  test-bar,  from 
an  aperture  in  the  side.  When  the  conversion  of  iron 
into  steel  appears  to  be  complete,  the  fire  is  extinguished  ; 
the  whole  is  left  to  cool,  for  six  or  eight  days  longer,  and 
is  then  removed. 

The  iron,  prepared  in  this  manner,  is  named  blistered- 
steel,  from  the  blisters  which  appear  on  its  surface.  To 
render  it  more  perfect,  it  is  subjected  to  the  action  of  the 
hammer,  in  nearly  the  same  manner  which  is  practised 
with  forged  iron  ;  it  is  beat  very  thin,  and  is  thus  ren- 
ered  more  firm  in  its  texture,  and  more  convenient  in  its 
^orm.     In  this  state  it  is  often  called  tilted-steel.     When 


ALLOCS   OF    STEEL.  241 

the  bars  are  exposed  to  heat,  in  a  furnace  sufficient  to 
soften  them,  and  afterwards  doubled,  drawn  out,  and 
welded,  the  product  is  called  shear-steel.  Cast-steel  is 
made,  by  fusing  bars  of  common  blistered-steel,  with  a 
flux  of  carbonaceous  and  vitreous  substances,  in  a  large 
crucible,  placed  in  a  wind-furnace.  When  the  fusion  is 
complete,  it  is  cast  into  small  bars,  or  ingots.  Cast-steel 
is  harder  and  more  elastic,  has  a  closer  texture,  and  re- 
ceives a  higher  polish,  than  common  steel.  It  is  capable 
of  still  further  improvement,  by  being  subjected  to  the 
action  of  the  hammer.* 

Steel  is  generally  prepared  from  malleable  iron.  It  can 
also  be  formed  from  crude  cast-iron,  as  in  Mr.  Lucas's 
method,  hereafter  described.  Several  varieties  of  cast- 
iron  have  been  used  for  this  purpose.  The  crude  iron 
from  certain  ores,  as  the  sparry  iron  ore,  is  capable  of  this 
conversion.  The  steel,  thus  obtained,  is  named  natural 
steel,  but  is  inferior  to  that  obtained  by  cementation. 

Alloys  of  Steel. — Messrs.  Stodart  and  Faraday  have 
succeeded  in  making  some  useful  alloys  of  steel  with  oth- 
er metals. f  Their  experiments  induced  them  to  believe, 
that  the  celebrated  Indian  steel,  called  icootz,  is  an  alloy 
of  steel  w^ith  small  quantities  of  silicium  and  aluminum  ; 
and  they  succeeded  in  preparing  a  similar  compound, 
possessed  of  all  the  properties  of  wootz.  They  ascer- 
tained that  silver  combines  with  steel,  forming  an  alloy, 
which,  although  it  contains  only  one  five  hundredth  of  its 
weight  of  silver,  is  superior  to  wootz,  or  to  the  best  cast- 
steel,  in  hardness.  The  alloy  of  steel  with  one  hundredth 
part  of  platinum,  though  less  hard  than  that  with  silver, 
possesses  a  greater  degree  of  toughness,  and  is,  there- 
fore, highly  valuable,  when  tenacity,  as  well  as  hardness, 
is  required.      The  alloy  of  steel  with  rhodium  even  ex- 

*  Writers  differ,  Iq  regard  to  the  proportion  of  carbon  contained  in 
cast-steel.  Mr.  Buttery,  in  Ure's  Dictionary,  states,  that  the  amount 
is  less  than  in  common  steel,  and  that  no  charcoal  is  added,  in  making 
it.  He  aUo  states,  that  it  does  not  melt,  at  a  welding  temperature, 
but  falls  to  pieces,  like  sand,  under  the  hammer,  and  the  parts  refug« 
to  become  again  united. 

t  Philosophical  Transactions,  for  1822. 

ir.  21  XII. 


242  ARTS   OF  METALLURGY. 

ceeds  the  two  former,  in  hardness.  The  compound  of 
steel  with  palladium,  and  of  steel  with  iridium  and  osmi- 
um, is  likewise  exceedingly  hard  ;  but  these  alloys  cannot 
be  applied  to  useful  purposes,  owing  to  the  rarity  of  the 
metals  of  which  they  are  composed.  M.  Berthier  has 
also  produced  a  useful  alloy,  by  combining  with  the  steel 
a  small  portion  of  chromium. 

Case  Hardening. — The  process  of  case-hardening  con- 
sists in  converting  the  surface  of  iron  into  steel,  and  is  used 
for  giving  a  superficial  hardness  to  various  instruments. 
It  is  effected,  by  enclosing  the  article  which  is  to  be  case- 
hardened,  in  a  box,  with  some  carbonaceous  substance, 
usually  animal  charcoal,  and  exposing  it  to  heat,  until  the 
surface  is  converted  into  steel.  The  same  term  is  some- 
times improperly  applied  to  the  method  of  chill-casting, 
which  has  been  already  mentioned. 

Tempering. — The  most  remarkable,  as  well  as  the 
most  useful,  of  the  properties  of  steel  is  the  power  which 
it  has  of  changing,  permanently,  its  degree  of  hardness,  by 
undergoing  certain  changes  of  temperature.  No  other 
metal,  says  Thenard,  is  known  to  possess  this  properly, 
and  iron  itself  acquires  it,  only  when  it  is  combined  with 
a  minute  portion  of  carbon.  If  steel  is  heated  to  redness, 
and  suddenly  plunged  in  cold  water,  it  is  found  to  become 
extremely  hard,  but,  at  the  same  time,  it  is  too  brittle  for 
use.  On  the  other  hand,  if  it  be  suffered  to  cool  very 
gradually,  it  becomes  more  soft  and  ductile,  but  is  defi- 
cient in  strength.  The  process  of  tempering  is  intended 
to  give  to  steel  instruments  a  quality,  intermediate  between 
brittleness  and  ductility,  which  shall  insure  them  the  propei 
degree  of  strength,  under  the  uses  to  which  they  are  ex- 
posed. For  this  purpose,  after  the  steel  has  been  suffi- 
ciently hardened.,  it  is  partially  softened,  or  let  down  to  the 
proper  temper,  by  heating  it  again,  in  a  less  degree,  or  to 
a  particular  temperature,  suited  to  the  degree  of  hardness 
required ;  after  which,  it  is  again  plunged  in  cold  water. 

Different  methods  have  been  pursued,  for  determining 
the  temperature,  proper  for  giving  the  requisite  temper  to 
different  instruments.  One  method  is,  to  observe  the 
shades  of  color  which  appear  on  the  surface  of  the  steel 


TEMPERING.  243 

and  succeed  each  other,  as  the  temperature  increases. 
Thus,  at  four  hundred  and  thirty  degrees  of  Fahrenheit, 
the  color  is  pale,  and  but  slightly  inclining  to  yellow.  This 
is  the  temperature  at  which  lancets  are  tempered.  At 
four  hundred  and  fifty  degrees,  a  pale  straw-color  appears, 
which  is  found  suitable  for  the  best  razors  and  surgical  in- 
struments. At  four  hundred  and  seventy  degrees,  a  full 
yellow  is  produced,  suitable  for  penkives,  common  razors, 
&c.  At  four  hundred  and  ninety  degrees,  a  brown  color 
appears,  which  is  used  to  temper  shears,  scissors,  garden- 
hoes,  and  chisels  intended  for  cutting  cold  iron.  At  five 
hundred  and  ten  degrees,  the  brown  becomes  dappled 
with  purple  spots,  which  show  the  proper  heat  for  tem- 
pering axes,  common  chisels,  plane-irons^  &c.  At  five 
hundred  and  thirty  degrees,  a  purple  color  is  established  ; 
and,  at  this  degree,  the  temper  is  given  to  table-knives 
and  large  shears.  At  five  hundred  and  fifty  degrees,  a 
bright  blue  appears,  used  for  swords  and  watch-springs. 
At  five  hundred  and  sixty  degrees,  the  color  is  a  full  blue, 
and  is  used  for  fine  saws,  augers,  &c.  At  six  hundred 
degrees,  a  dark  blue,  approaching  to  black,  has  become 
settled,  and  is  attended  with  the  softest  of  all  the  grades 
of  temper,  used  only  for  the  larger  kinds  of  saws. 

Another  method  of  giving  the  requisite  temper  has 
been  practised  upon  various  articles.  The  pieces  of 
steel  are  covered  with  oil  or  tallow,  or  put  into  a  vessel 
containing  either  of  these  ingredients,  and  heated  over  a 
moderate  fire.  The  appearance  of  the  smoke,  from  the 
oil  or  tallow,  indicates  the  degree  of  heat.  If  the  smoke 
just  appear,  the  temper  corresponds  with  that  indicated 
by  the  straw-color,  when  the  metal  is  heated  alone.  If 
so  much  heat  is  applied,  that  a  black  smoke  arises,  this 
points  out  a  different  degree  of  hardness  ;  and  so  on,  till 
the  vapor  catches  flame.  By  this  method,  a  number  of 
pieces  may  be  done,  at  once,  with  comparatively  littip 
trouble,  and  the  heat  is  also  more  equally  applied. 

A  still  more  accurate  method  of  producing  any  desired 
degree  of  temper  is,  to  immerse  the  steel  in  some  fluid 
medium,  the  temperature  of  which  is  kept  regulated,  by 
the  thermometer.     Thus  oil,  which  boils  at  about  six 


244  ARTS   OF  METALLURGY 

hundred  degrees,  may  be  used,  for  this  purpose,  at  any 
degree  of  heat  which  is  below  that  number  of  degrees. 
Mr.  Parkes  has  recommended  the  employment  of  metal- 
lic baths,  chiefly  composed  of  lead  and  tin,  in  different 
proportions,  which  pass  into  fusion,  at  definite  tempera- 
tures, and  which  can  be  used  for  tempering  steel,  as  soon 
as  they  arrive  at  their  melting  points.*  f 

*  The  following  table  of  metallic  baths  is  given,  in  Parkes's  Cheni 
ical  Essays,  Appendix  to  vol.  ii. 

No.    Edge  Tools  to  be  tempered  in  the  various  Composition  Temper- 
Baths.                                        of  the  Bath.  Fahren. 

1  Lancets,  in  a  bath,  composed  of  7     lead  4  tin         420^ 

2  Other  surgical  instruments,  7^  lead  4  tin         430 

3  Razors,  &c.,  8     lead  4  tin         442 

4  Penknives,  gnd  some  implements  of 

surgery,  8^  lead  4  tin         450 

5  Larger  penknives,  scalpels,  &c.,  10     lead  4  tin         470 

6  Scissors,  shears,  garden-hoes,  cold 

chisels,  &c.,  14     lead  4  tin         490 

7  Axes,  firmer  chisels,  plane-irons, 

pocket-knives,  &c.,  19     lead  4  tin         509 

8  Table-knives,  large  shears,  &,c.,  30     lead  4  tin         530 

9  Swords,  watch-springs,  &c.,  48     lead  4  tin         550 

10  Large  springs,  daggers,  augers,  small 

fine  saws,  &c.,  50     lead  2  tin  558 

11  Pit-saws,  band-saws,  and  some  par- 

ticular springs.  Boiling  linseed  oil     600 

12  Articles  which  require  to  be  still 

somewhat  softer.  Melting  lead         612 

t  Formerly,  no  man  in  Great  Britain  knew  how  to  temper  a  sword 
m  such  a  way,  that  it  would  bend,  for  the  point  to  touch  the  heel  and 
spring  back  again  uninjured,  except  one  Andrew  Ferrara,  who  resided 
in  the  Highlands  of  Scotland.  The  demand  which  this  man  had  for  hi< 
swords  was  so  great,  that  he  employed  workmen  to  forge  then),  and 
spent  all  his  own  time  in  tempering  them  ;  and  found  it  necessary, 
even  in  the  day  time,  to  work  in  a  dark  cellar,  that  he  might  be  better 
able  to  observe  the  progress  of  the  heat,  and  that  the  darkness  of  his 
workshop  might  favor  him  in  the  nicety  of  the  operation. 

The  swords,  which  were  formerly  in  the  highest  repute,  were  made 
at  Damascus,  in  Syria.  The  method,  by  which  these  were  made,  has 
long  been  lost,  or  perhaps  it  was  never  thoroughly  known  to  Europe- 
ans ;  but  from  their  striated  appearance,  it  has  been  supposed  that 
they  were  formed  by  alternate  layers  of  extremely  thin  plates  of  iron 
and  steel,  bound  together  with  iron  wire,  and  then  firmly  cemented 
together  by  welding.  These  weapons  never  broke,  even  in  the  hard- 
est conflict,  and  retained  so  powerful  an  edge,  as  to  be  capable  of  cut- 
ting through  armor.  Various  other  explanations  have  been  given  in 
regard  to  the  character  and  structure  of  the  Damascus,  or  damasked 
steel. 


CUTLERY.  245 

Cutlery. — Under  the  head  of  cutlery,  are  comprehend- 
ed numerous  instruments,  designed  for  cutting  or  penetra- 
tion, and  which  are  made  of  steel,  mostly,  by  the  proces- 
ses of  forging,  tempering,  grinding,  and  polishing.  The 
inferior  kinds  of  cutlery  are  made  of  bhstered-steel,  weld- 
ed to  iron.  Tools  of  a  better  quahty  are  manufactured 
from  shear-steel,  while  the  sharpest  and  most  dehcate  in- 
struments are  formed  of  cast-steel. 

The  first  part  of  the  process  consists  in  forging,  and  is 
varied,  according  to  the  kind  of  article  to  be  formed. 
Common  table-knives .,  have  the  blade  forged  of  steel,  and 
welded  to  a  piece  of  iron,  out  of  which  the  shoulder,  and 
part  which  entei*s  the  handle,  are  made,  the  shape  being 
given  to  them  by  hammering  in  a  die  and  swage.  They 
are  afterwards  tempered  and  ground.  Forks  are  made 
by  forging  the  shank,  and  flattening  the  other  end  to  the 
length  intended  for  the  prongs.  The  prongs  are  made, 
by  stamping  the  metal,  at  a  white  heat,  between  two  dies, 
the  uppermost  of  which  is  attached  to  a  heavy  weight, 
and  falls  from  a  height.  The  shape  is  thus  given  to  the 
fork,  leaving,  however,  a  flat  thin  piece  of  metal  between 
the  prongs,  w^hich  is  afterwards  cut  out  with  a  fly-press. 
They  are  subsequently  filed,  bent,  hardened,  and  pol- 
ished. 

Blades  of  penknives  are  forged  from  the  end  of  a  rod 
of  steel,  and  cut  qfl*,  together  with  metal  enough  to  form 
the  joint.  The  smal!  recess,  in  which  the  nail  is  insert- 
ed, to  open  the  knife,  is  made  with  a  curved  chisel,  while 
the  steel  is  hot.  Razors  are  forged  from  cast-steel, 
much  in  the  same  manner  as  knives.  The  anvil  is  com- 
monly a  httle  rounded,  at  the  sides,  for  the  purpose  ol 
making  the  sides  of  the  razor  a  little  concave,  and  the 
edge  thinner.  In  forging  scissors^  the  shape  is  given  to 
the  different  parts,  by  hammering  them  upon  different  in- 
dented surfaces,  called  bosses.  The  bows  which  receive 
the  finger  and  thumb  are  made,  by  punching  a  hole  in  the 
metal,  and  enlarging  it,  by  hammering  it  round  a  tool, 
called  a  beak  iron.  The  halves  are  finished  by  filing  and 
grinding,  and  afterwards  united  by  a  joint.  Saws  are 
made  from  steel-plates,  rolled  for  the  purpose,  and  have 
21* 


246  ARTS    OF  METALLURGY. 

their  leeth  cut  and  finished  by  fiHng,  and  set  by  a  suita- 
ble instrument.  Axes^  adzes,  and  other  large  tools,  are 
forged  from  iron,  and  have  a  steel  piece  welded  on,  of 
the  proper  size,  to  form  the  edge. 

To  enable  the  steel  to  be  wrought,  it  is  brought  to  its 
softest  state  ;  but  after  the  shape  is  given  to  the  instrument, 
the  steel  is  hardened  and  tempered,  by  the  methods  al- 
ready described.  The  remaining  part  of  the  manufacture 
consists  in  grinding,  polishing,  and  setting  the  instrument, 
to  produce  a  smootli  surface  and  a  sharp  edge.  The 
grinding  is  performed  upon  stones,  of  various  kinds, 
among  which,  freestone  is,  perhaps,  the  most  common. 
These  stones  are  made  to  revolve  by  machinery,  and 
move  with  prodigious  velocity,  so  that  the  surface,  in 
some  cases,  passes  over  six  or  seven  hundred  feet,  in  a 
second,  and  stones  have  been  burst  by  their  own  centri- 
fugal force.  For  grinding  flat  surfaces,  hke  those  of 
saws,  the  largest  stones  are  used  ;  while,  for  concave 
surfaces,  hke  the  sides  of  razors,  smaller  stones  are  used, 
on  account  of  their  greater  convexity.  The  internal  sur- 
faces of  scissors,  forks,  &c.,  which  cannot  be  apphed  to 
the  stone,  are  ground  with  sand  and  emery,  applied  with 
instruments  of  wood,  leather,  and  other  elastic  substan- 
ces. The  last  polish  is  given  by  the  impure  oxide  of 
iron,  called  colcothar-crocus,  and  by  the  French,  Rouge 
c?'  Angleterre.  The  edges  are  lastly  set  with  hones  and 
whetstones,  according  to  the  degree  of  keenness  required. 
The  test,  used  by  cutlers,  for  determining  the  goodness 
of  the  edge  and  point  of  a  lancet,  is,  that  it  shall  pass 
through  a  piece  of  soft  leather,  without  sensible  resis- 
tance. JVeei/esare  polished,  by  tying  them  in  large  bun- 
dles, with  emery  and  oil,  and  rolling  them  under  a  heavy 
plank,  till  they  become  smooth,  by  mutual  attrhion.  The 
shape  is  previously  given,  and  the  eye  made  with  a  steel 
punch. 

A  process  has  been  invented  by  Mr.  Lucas,  for  con- 
verting edge-tools,  nails,  &c.,  made  of  cast-iron,  into 
good  steel.  It  consists  in  stratifying  the  cast  articles, 
in  cylindrical  metalHc  vessels,  with  native  oxide  of  iron, 
and  then  submitting  the  whole  to  a  regular  heat,  in  a  fur- 


ARTS  OF  VITRIFICATION.  247 

nace  built  for  the  purpose.  It  is  not,  however,  necessary 
that  the  oxide  employed  should  be  a  native  oxide,  any 
artificial  oxide  being  equally  efFectual. 

The  cast-iron,  of  which  this  cutlery  is  made,  is  brittle, 
in  the  first  instance,  hke  other  cast-iron,  in  consequence 
of  the  carbon  contained  in  it ;  but  the  great  heat  which  it 
undergoes,  aided  by  the  pulverized  oxide,  separates  a  part 
of  the  carbon.  This,  uniting  with  the  oxygen  of  the 
ground  oxide  of  iron,  is  dissipated  in  the  state  either  of 
carbonic  oxide,  or  carbonic  acid  gas,  and  the  articles  are* 
then  converted  into  a  state  nearly  similar  to  that  of  good 
cast-steel  cutlery.  They  do  not,  however,  receive  so 
fine  an  edge,  and  do  not  bear  hardening  and  tempering,  in 
the  common  manner. 

Works  of  Reference. — Murray's  System  of  Chemistry,  4 
vols.  8vo.  1806  ; — Parkes's  Chemical  Essays,  2  vols.  Svo.  1823  ; — 
Gray's  Operative  Chemist,  Svo.  1828  ; — Dumas,  Traite  de  Chi/nie 
Appliquee  aux  Arts,  SfC,  4  torn.  8vo.  1828-9  ; — Fourcroy,  Sys- 
ieme  des  Connaissances  Chimiques,  11  tom.  1801  ; — Aiken's  Dic- 
tionary of  Chemistry  and  Mineralogy,  2  vols.  4to.  1807  ; — Martin's 
Circle  of  Mechanic  Arts,  4to.  1818  ; — Emporium  of  Arts  and  Scien- 
ces, Philadelphia,  1812-14  ;  Franklin  Journal,  Philadelphia,  1826,  and 
after  ; — Rees'  Cyclopedia,  various  heads  ; — Ure's  Dictionary  of 
Chemistry  ; — Thenard,  Traite  de  Chimie,  5  tom.  Svo.  1824  ; — 
Works  of  Bergman,  Klaproth,  Lewis,  &c.  ; — LardnerN 
Cabinet  Cyclopedia,  3  vols.  12  mo.  entitled,  Manufactures  in  Metal 


CHAPTER.  XXI. 


ARTS    OF    VITRIFICATION. 


Glass,  Materials,  Crown  Glass,  Fritting,  Melting,  Blowing,  Anneahng, 
Broad  Glass,  Flint  Glass,  Bottle  Glass,  Cylinder  Glass,  Plate  Glass, 
Moulding,  Pressing,  Cutting,  Stained  Glass,  Enamelling,  Artificial 
Gems,  Devitrification,  Reaumur's  Porcelain,  Crystallo-Ceramie. 
Glass  Thread,  Remarks. 

A  GREAT  number  of  earths,  and  other  mineral  bodies, 
after  being  fused,  do  not  resume  their  original  character, 
upon  cooling,  but  pass  into  a   dense,  hard,  shining,  and 


248  ARTS   OF  VITRIFICATION. 

brittle,  state,  having  the  character  of  glass  ;  and  are  thus 
said  to  be  vitrified.  Most  of  these  substances  do  not 
immediately  become  hard,  upon  the  reduction  of  their 
temperature,  but  go  througa  an  intermediate,  or  ductile, 
state,  in  which  a  combination  of  softness  with  tenacity,  en- 
ables them  to  be  wrought  into  articles  of  use  and  orna- 
ment. Of  these,  common  glass  is  the  most  important, 
while  enamels,  artificial  gems,  &c.,  belong  to  the  same 
s})ecies  of  manufacture. 

Glass. — Glass  is  a  compound  substance,  artificially 
produced,  by  the  combination  of  silicious  earth  with  al- 
kalies, and,  in  some  cases,  with  other  metallic  oxides. 
These  substances,  being  melted  together  at  a  high  tem- 
perature, unite,  lose  their  opacity,  and  are  fused  into  a 
homogeneous  mass,  which,  on  cooling,  has  the.  properties 
of  hardness,  transparency,  and  brittleness. 

Materials.* — The  most  important  ingredient,  and,  in 
fact,  the  basis,  of  transparent  glass,  is  silica,  or  oxide  of 
silicium.  This  earth,  nearly  in  a  state  of  purity,  is  found 
in  the  sand  of  certain  situations,  and  also  in  common  flint, 
and  quartz  pebbles.  Sand  has  the  advantage  of  being 
already  in  a  state  of  minute  division,  not  requiring  to  be 
pulverized.  Pure  silicious  sand,  proper  for  the  glass  fur- 
nace, is  found  in  many  localities.  A  great  portion  of 
that  used  in  the  United  States  is  taken  from  the  banks 
of  the  Delaware.  When  flints,  or  quartz,  are  employed, 
they  must  be  first  reduced  to  powder,  which  is  done  by 
heating  them  red  hot,  and  plunging  them  in  cold  water. 
This  causes  them  to  whiten  and  fall  to  pieces  ;  after  which, 
they  are  ground  and  sifted,  before  they  are  ready  for  the 
furnace. 

An  alkaline  substance,  either  potash  or  soda,  is  the 
second  ingredient  in  glass.  For  the  finer  kinds  of  glass, 
pure  pearlash  is  used,  or  soda,  procured  by  decomposing 

*  The  term  metals^  which  appears  to  be  a  corruption  of  materials, 
13  in  common  use,  among  glass-manufacturers,  to  express  the  ingredi- 
ents, or  substances,  upon  which  their  operations  are  performed.  The 
same  term  is  employed,  in  a  similar  sense,  by  other  manufacturers  and 
artists,  and  by  some  writers  on  road-making.  The  term  metal,  in  the 
singular,  is  applied  to  glass,  in  a  state  of  fusion 


CROWN-GLASS.  249 

sea-salt  ;  but,  for  the  inferior  sorts,  impure  alkalies,  and 
even  wood-ashes,  are  made  to  answer  the  purpose.  Lime 
is  often  employed,  in  small  quantities  ;  also  borax,  a  salt 
which  facihtates  the  fusion  of  the  silica. 

Instead  of  the  common  alkalies,  the  sulphate  of  soda 
may  be  employed,  in  glass-making.  But,  in  this  case, 
it  is  necessary  to  liberate  the  alkali,  by  decomposing  the 
sulphuric  acid  of  the  salt.  This  may  be  done,  by  char- 
coal, or,  in  flint-glass,  by  metallic  lead.  Lime  is  also 
used  with  this  salt. 

Of  the  metaUic  oxides,  which  are  added  in  different 
cases,  the  deutoxide  of  lead  (red  lead)  is  the  most  com- 
mon. This  substance  renders  flint-glass  more  fusible, 
heavy,  and  tough,  and  more  easy  to  be  ground  and  cut. 
At  the  same  time,  it  imparts  to  it  a  greater  brilliancy,  and 
refractive  power.  Black  oxide  of  manganese,  in  small 
quantities,  has  the  effect  of  cleansing  the  glass,  or  of  ren- 
dering it  more  colorless  and  transparent.  This  effect  it 
seems  to  produce,  by  imparting  oxygen  to  the  carbona- 
ceous impurities,  thus  forming  with  them  carbonic  acid, 
which  subsequently  escapes.  Common  nitre  produces  a 
similar  effect.  If  too  much  manganese  be  added,  it  com- 
municates a  purple  tinge  to  the  glass,  which,  however, 
may  be  destroyed,  by  a  little  charcoal  or  wood.  Arsen- 
ious  acid,  (white  arsenic,)  in  small  quantities,  promotes 
the  clearness  of  glass  ;  but,  if  too  much  be  used,  it  com- 
municates a  milky  whiteness.  Its  use,  in  drinking-ves- 
sels,  is  not  free  from  danger,  when  the  glass  contains 
so  much  alkali,  as  to  render  any  part  of  it  soluble  in 
acids. 

Crown  Glass. — Glass  is  of  various  kinds,  which  are 
named,  not  only  from  the  character  of  their  ingredients, 
but  from  the  mode  in  which  they  are  wrought.  The  name 
of  croicn-glass  is  given  to  the  best  kind  of  window-glass, 
that  which  is  hardest,  and  most  free  from  color.  It  is 
made  almost  entirely  of  sand  and  alkali,  and  a  litde  lime, 
without  lead,  or  any  other  metallic  oxide,  except  a  minute 
quantity  of  manganese,  and  sometimes  of  cobalt,  which  are 
added,  to  counteract  the  effect  of  any  impurities,  in  giving 
color  to  the  glass.     Crown-glass  requires  a  2;reatpr  heat, 


250  ARTS   OF  VITRIFICATION. 

to  melt  its  ingredients,  than  those  kinds,  which  contain  a 
larger  quantity  of  metaUic  oxide,  especially  of  lead. 

Frilting, — After  the  materials  have  been  intimately 
mixed,  they  are  subjected  to  the  operation,  called/n/^i?i^. 
This  consists  in  exposing  them  to  a  dull,  red  heat,  which 
is  not  sufficient  to  produce  their  fusion.  The  use  of  this 
process  is,  to  drive  off  the  carbonic  acid,  and  other  gase- 
ous and  volatile  matters,  which  would  otherwise  prove 
troublesome,  by  causing  the  materials  to  swell  up  in  the 
glass-pots.  The  heat  is  gradually  increased,  and  the  ma- 
terials constantly  stirred,  for  some  hours,  until  they  unite 
into  a  soft,  adhesive  mass  ;  the  alkali  having  gradually 
combined  with  the  silicious  earth.  The  reason  why  the 
fritting  is  conducted  at  a  low  heat  is,  that,  if  a  high  tem- 
perature were  applied,  at  once,  the  alkali  would  be  driven 
off,  before  it  had  time  to  combine  with  the  silica. 

Melting. — The  homogeneous  mass,  or  frit^  is  next 
transferred  to  the  glass-pots  of  the  melting  furnace.  These 
are  crucibles,  made  of  the  most  refractory  clays  and  sand. 
A  quantity  of  old  glass  is  commonly  placed  upon  the 
top  of  the  frit,  and  the  heat  of  the  furnace  is  raised  to 
its  greatest  height,  at  which  state  it  is  continued  for  thirty 
or  forty  hours.  During  this  time,  the  materials  become 
perfectly  united,  and  form  a  transparent,  uniform,  mass, 
free  from  specks  and  bubbles.  The  whole  is  then  suf- 
fered to  cool  a  little,  by  slackening  the  heat  of  the  fur- 
nace, until  it  acquires  sufficient  tenacity  to  be  wrought. 

Blowing. — The  formation  of  window-glass  is  effected, 
by  blowing  the  melted  matter,  or  metal.,  as  it  is  called, 
jnto  hollow  spheres,  which  are  afterwards  made  to  ex- 
pand into  circular  sheets.  The  workman  is  provided 
with  a  long,  iron  tube,  one  end  of  which  he  thrusts  into 
the  melted  glass,  turning  it  round,  until  a  certain  quantity, 
sufficient  for  the  purpose,  is  gathered.^  or  adheres  to  the 
extremity.  The  tube  is  then  withdrawn  from  the  furnace, 
the  lump  of  glass,  which  adheres,  is  rolled  upon  a  smooth 
iron  table,  and  the  workman  blows  strongly,  with  his 
mouth,  through  the  tube.  The  glass,  in  consequence  of 
its  ductility,  is  gradually  inflated,  like  a  bladder,  and  is 
prevented  from  falling  off,  by  a  rotary  motion,  constantly 


ANNEALING. BROAD-GLASS.  251 

communicated  to  the  tube.  The  mflation  is  assisted  by 
the  heat,  which  causes  the  air  and  moisture  of  the  breath 
to  expand,  with  great  power.  Whenever  the  glass  be- 
comes so  stiff,  from  coohng,  as  to  render  the  inflation 
difficuh,  it  is  again  held  over  the  fire  to  soften  it,  and  the 
blowing  is  repeated,  until  the  globe  is  expanded  to  the 
requisite  thinness.  It  is  then  received,  by  another  work- 
n'jr.n,  upon  an  iron  rod,*  while  the  blowing-iron  is  detach- 
ed. It  is  now  opened  at  its  extremity,  and,  by  means  of 
the  centrifugal  force,  acquired  from  its  rapid  whirling,  it 
spreads  into  a  smooth,  uniform  sheet,  of  equal  thickness 
throughout,  excepting  a  prominence  at  the  centre,  where 
the  iron  rod  was  attached. 

Annealing. — After  the  glass  has  received  the  shape 
which  it  is  to  retain,  it  is  transferred  to  a  hot  chamber,  or 
annealing  furnace,  in  which  its  temperature  is  gradually 
reduced,  until  it  becomes  cold.  This  process  is  indis- 
pensable to  the  durability  of  glass  ;  for,  if  it  is  cooled  too 
suddenly,  it  becomes  extremely  brittle,  and  flies  to  pieces, 
upon  the  slightest  touch  of  any  hard  substance.  This 
effect  is  shown^n  the  substances  called  Rupert's-drops, 
which  are  made,  by  suddenly  cooHug  drops  of  green  glass, 
by  letting  them  fall  into  cold  water.  These  drops  fly  to 
pieces,  with  an  explosion,  whenever  their  smaller  extrem- 
ity is  broken  off.  The  BGlogna-phials,  and  some  other 
vessels  of  unannealed  glass,  break  into  a  thousand  pieces, 
if  a  flint,  or  other  hard  and  angular  substance,  is  dropped 
Into  M^em.  This  phenomenon  seems  to  depend  upon 
some  permanent  and  strong  inequality  of  pressure  ;  for 
when  these  drops  are  heated  so  red  as  to  be  soft,  and 
left  to  cool,  gradually,  the  property  of  bursting  is  lost,  and 
the  specific  gravity  of  the  drop  is  increased. 

Broad  Glass. — This  is  a  coarser  kind  of  window-glass, 
and  is  made  from  sand,  with  kelp  and  soap-boilers'  waste 
It  is  blo\\Ti  into  hollow  cones,  about  a  foot  in  diameter, 
and  these,  while  hot,  are  touched  on  one  side  with  a  cold 
iron,  dipped  in  water.  This  produces  a  crack,  which 
runs  through  the  length  of  the  cone,  nearly  in  a  right  line 

*  Called  a  punt,  or  punting-iron. 


252  ARTS    OF   VITRIFICATION. 

The  glass  then  expands  into  a  sheet,  in  its  form  resemb- 
ling, somewhat,  the  shape  of  a  fan.  This  appears  to  have 
been  one  of  the  oldest  methods  of  manufacturing  glass. 

Flint  Glass. — Flint-glass,  so  called,  from  its  having 
been  originally  made  of  pulverized  flints,  differs  from  win- 
dow-glass, in  containing  a  large  quantity  of  the  red  oxide 
of  lead.  The  proportions  of  its  materials  differ  ;  but,  in 
round  numbers,  it  consists  of  about  three  parts  of  fine 
sand,  two  of  red  lead,  and  one  of  pearlash,  with  small 
quantities  of  nitre,  arsenic,  and  manganese.  It  fuses  at  a 
lower  temperature  than  crown-glass,  has  a  beautiful  trans- 
parency, a  great  refractive  power,  and  a  comparative  soft- 
ness, which  enables  it  to  be  cut  and  polished,  with  ease. 
On  this  account,  it  is  much  used  for  glass  vessels,  of  every 
description,  and  especially  those  which  are  intended  to  be 
ornamented,  by  cutting.  It  is  also  employed  for  lenses, 
and  other  optical  glasses.  Flint-glass  is  worked,  by  blow- 
ing, moulding,  pressing,  and  grinding.  Articles  of  com- 
plex form,  such  as  lamps  and  wine-glasses,  are  formed 
in  pieces,  which  are  afterwards  joined,  by  simple  contact, 
while  the  glass  is  hot.  It  appeal's,  that  the  red  lead,  used 
in  the  manufacture  of  flint-glass,  gives  up  a  part  of  its  oxy- 
gen, and  passes  to  the  state  of  a  protoxide. 

Bottle  Glass. — Common  green  glass,  of  which  bottles 
are  made,  is  the  cheapest  kind,  and  formed  of  the  most 
ordinary  materials.  It  is  composed  of  sand,  with  lime, 
and  sometimes  clay,  and  alkaline  ashes,  of  any  kind,  such 
as  kelp,  barilla,  or  even  wood-ashes.  The  green  color 
is  owing  to  the  impurities  in  the  ashes,  but  chief!}',  to 
oxide  of  iron.  This  glass  is  hard,  strong,  and  well  vitri- 
fied. It  is  less  subject  to  corrosion,  by  strong  acids,  than 
flint-glass ;  and  is  superior  to  any  cheap  material,  for  the 
purposes  to  which  it  is  ordinarily  applied. 

Cylinder  Glass. — The  plates  of  crown-glass,  which 
^re  obtained  in  the  common  manner,  by  blowing  them  in 
circular  plates,  afford  the  common  material  for  window- 
glass  ;  being  cut  into  squares,  by  first  marking  the  surface 
deeply,  with  a  diamond,  and  then  breaking  the  glass,  m 
the  same  directions  ;  the  crack  always  following  the  exact 
course  of  the  incision,  made  by  the  diamond.      But  there 


PLATE-GLASS.  253 

is  always  a  loss,  or  waste,  in  cutting  squares,  from  a  cir~ 
cular  plate  ;  besides  which,  they  can  never  be  very  large, 
owing  to  the  protuberance,  or  bulVs-eye,  which  fills  the 
centre  of  the  plate  ;  so  that  a  square  can  never  be  larger, 
than  can  be  described  within  less  than  half  the  circle. 
To  remedy  this  disadvantage,  plates  for  looking-glasses, 
and  others,  of  large  size,  are  executed  in  a  different  way, 
either  by  blowing  them  in  cyhnders,  or  by  casting  them 
in  plates,  at  first. 

Cyhnder  glass  is  blown,  at  first,  in  spheres,  like  window- 
glass.  These  are  elongated  into  spheroids,  by  a  swinging 
motion,  which  the  workman  gives  to  his  rod.  The  ends 
of  this  spheroid  are  successively  perforated,  thus  conver- 
ting it  into  an  irregular  cylinder.  One  side  of  this  cylinder 
is  cut  through,  with  shears,  and  the  glass  is  laid  upon  a 
flat  surface,  where  it  expands  into  a  uniform  plate,  with- 
out any  protuberance.  It  is  then  annealed,  by  diminishing 
the  heat,  in  the  common  way.  When  the  plates  are  in- 
tended for  looking-glasses,  the  finest  materials  are  used, 
and  the  heat  kept  at  its  greatest  height,  for  a  long  time, 
to  dissipate  all  impurities,  and  remove  any  specks  or  bub- 
bles. 

Plate  Glass. — Looking-glass  plates  may  be  blown  in 
cyhnders,  when  they  do  not  exceed  about  four  feet  in 
length.  But  they  cannot  well  be  blown,  of  a  larger  size 
than  this,  from  such  a  quantity  of  glass  as  the  rod  will 
take  up,  without  becoming  too  thin  to  bear  pohshing. 
Plates,  however,  may  be  made  of  more  than  double  this 
size,  by  another  process,  which  is  called  casting,  and 
which  is  the  only  mode  by  which  very  large  plates  are 
produced. 

When  glass  is  to  be  cast,  it  is  melted,  in  great  quanti- 
ties, in  large  pots,  or  reservoirs,  until  it  is  in  a  state  of 
perfect  fusion,  in  which  state  it  is  kept  for  a  long  time. 
It  is  then  drawn  out,  by  means  of  iron  cisterns,  of  consid- 
erable size,  which  are  lowered  into  the  furnace,  filled,  and 
raised  out,  by  machinery.  The  glass  is  poured  out  from 
these  cisterns,  upon  tables  of  polished  copper,  of  a  large 
size,  having  a  rim  elevated  as  high  as  the  intended  thick- 
ness of  the  plate.  In  order  to  spread  it  perfectly,  and  tc 
II.  22    .  XII. 


254  ARTS   OF  VITRIFICATION. 

iniike  the  two  surfaces  parallel,  a  heavy  roller  of  polished 
copper,  weighing  five  hundred  pounds,  or  more,  is  rolled 
over  the  plate,  resting  upon  the  rim,  at  the  edges.  The 
glass,  which  is  beginning  to  grow  stift\  is  pressed  down, 
and  spread  equally,  the  excess  being  driven  before  the  rol- 
ler, till  it  falls  oft'  at  the  extremity  of  the  table.  The  plate 
is  then  ready  to  be  annealed. 

As  the  plates,  which  are  cast  for  looking-glasses,  are 
always  uneven  and  dull,  at  their  surface,  it  is  necessary 
to  grind  and  polish  them,  before  they  are  fit  for  use. 
The  process,  employed  for  producing  a  perfectly  even 
and  smooth  surface,  is  very  similar  to  that  employed  in 
polishing  marble ;  except  that  the  glass,  being  the  harder 
substance,- requires  more  labor  and  nicety,  in  the  oper- 
ation. The  plate  to  be  polished  is  first  cemented  to  a 
table  of  wood  or  stone,  vv'ith  plaster  of  Paris.  A  quan- 
tity of  wet  sand  or  emery  is  spread  upon  it,  and  anoth- 
er glass  plate,  similarly  cemented  to  another  wooden  sur- 
face, is  brought  in  contact  with  it.  The  two  plates  are 
then  rubbed  together,  until  the  surfaces  have  become  mu- 
tually smooth  and  plane.  The  emery,  which  is  first  used, 
is  succeeded  by  emery  of  a  finer  grain,  and  the  last  polish 
is  given  by  colcothar  or  putty.  When  one  surface  has 
become  perfectly  polished,  the  cement  is  removed,  the 
plate  turned,  and  the  opposite  side  pohshed  in  the  same 
manner. 

As  the  grinding  of  glass  causes  an  expenditure  of  a 
considerable  portion  of  its  substance,  a  great  waste  of 
glass  takes  place,  when  foreign  materials  are  employed, 
in  the  manner  which  has  been  described.  To  prevent 
this  loss,  a  more  economical  mode  has  been  introduced, 
in  which  the  glass  is  ground  with  pure  flint,  reduced  to 
powder.  The  mixture  of  glass  and  flint,  which  is  left, 
after  the  operation,  is  valuable,  for  forming  fresh  glass. 

JMoulding. — A  variety  of  ornamental  forms  are  pro- 
duced, upon  the  surface  of  glass  vessels,  by  impressions 
given  to  them  with  a  metallic  mould,  while  the  glass  is  in 
a  hot  state.  Flint-glass  is  the  kind  which  is  used  for 
articles,  intended  to  possess  much  brilliancy ;  but  coarser 
kinds,  even  of  colored  glass,  are  also  subjected  to  the 


PRESSING. CUTTING.  255 

same  process.  The  simplest  manner,  in  which  the  ope- 
ration is  conducted,  consists,  in  blowing  the  glass  into  the 
mould,  till  it  receives  the  impression,  on  its  outside.  For 
this  purpose,  a  quantity  of  glass,  sufBcient  to  form  the 
intended  vessel,  is  taken  up  on  the  end  of  a  pipe,  and  in- 
serted at  the  top  of  the  mould.  The  workman  then  blows, 
with  his  mouth,  till  a  hollow  portion  of  glass  is  driven  into 
the  mould,  and  expands,  so  as  to  fill  every  part,  and  re- 
ceive an  impression  on  its  outside.  The  mould  is  usual- 
ly made  of  copper,  with  the  figure  cut  on  its  inside,  and 
opens  with  hinges,  to  permit  the  glass  to  be  inserted,  and 
taken  out.  As  the  mould  is,  of  necessity,  much  cold- 
er than  the  glass,  the  latter  substance  is  chilled,  at  its 
surface,  as  soon  as  it  comes  in  contact  with  the  cop- 
per ;  hence  its  ductility  is  impaired,  and  the  impression 
given  is  never  so  sharp  as  that  w^iich  is  obtained  with 
substances,  which  are  nearly  at  the  same  temperatures. 
Moulded  bottles,  phials,  decanters,  &c.,  are  made  in  this 
way. 

Pressing. — An  improvement  has  been  made,  in  the 
process  of  moulding  glass,  by  subjecting  the  material  to 
pressure,  on  the  inside  and  outside,  at  the  same  time,  by 
different  parts  of  a  mould,  which  are  brought  suddenly 
together,  by  mechanical  power.  This  process  has  been 
carried  to  great  perfection,  in  several  of  the  manufacto- 
ries in  this  country,*  and  produces  specimens,  which 
compare  with  cut  glass,  in  the  accuracy  and  beauty  of 
the  workmanship.  It  is  applied  only  to  solid  articles, 
and  to  vessels  which  are  not  contracted  at  top.  The 
hot  glass  being  dropped  into  the  mould,  a  part,  called  the 
follower,  answering  to  the  inside  or  top  of  the  vessel,  or 
other  article,_is  immediately  pressed  down  upon  it,  by  a 
lever,  and  the  glass  is  thus  stamped  with  a  very  distinct 
impression  of  the  figure,  on  both  sides  at  once.  The 
glass  vessel  is  sometimes  transferred  from  the  mould  to 
another  receptacle,  called  the  receiver,  in  order  to  pre- 
serve its  shape,  till  it  is  cool  enough  to  stand. 

Cutting. — The  name  of  cut-glass  is  given,  in  com 

*  Particularly,  at  Lee  Anere's  Point,  and  Sandwich 


256  ARTS    OF  VITRIFICATION. 

merce,  to  glass  which  is  ground  and  polished,  in  figures, 
with  smooth  surfaces,  appearing  as  if  cut  by  incisions  of 
a  sharp  instrument.  This  operation  is  chiefly  confined 
to  flint-glass,  which,  being  more  tough,  soft,  and  brilliant, 
than  the  other  kinds,  is  more  easily  WTOught,  and  pro- 
duces specimens  of  greater  lustre.  An  establishment  for 
cutting  glass,  contains  a  great  number  of  small  wheels,  of 
stone,  metal,  and  wood,  which  are  made  to  rev^olve  rap- 
idly, by  a  steam-engine  or  other  power.  The  cutting 
of  the  glass  consists  entirely,  in  grinding  away  successive 
portions,  by  holding  them  upon  the  surface  of  these  wheels. 
The  first,  or  rough  cutting,  is  sometimes  given  by  wheels 
of  stone,  resembling  grindstones.  Afterwards,  wheels 
of  iron  are  used,  having  their  edges  covered  with  sharp 
sand,  or  with  emery,  in  different  states  of  fineness.  The 
last  polish  is  given  by  brush-wheels,  covered  with  putty, 
which  is  an  oxide  of  tin  and  lead.  To  prevent  the  fric- 
tion from  exciting  so  much  heat,  as  to  endanger  the  glass 
a  small  stream  of  water  continually  drops  upon  the  sui 
face  of  the  wheel. 

Stained  Glass. — The  name  of  staining  has  been  ap 
plied  to  the  process,  by  which  painting,  with  vitrifiable 
colors,  is  executed  upon  the  surface  of  glass.  The  pig- 
ments used  are,  chiefly,  metallic  oxides,  which  do  not  ex- 
hibit their  full  color,  until  they  have  been  exposed  to  the 
heat  of  the  furnace.  This  art  has  been  repeatedly  des- 
cribed, as  being  no  longer  known  ;  but  this  is  not  the 
fact,  except  in  respect  to  some  particular  colors,  which 
are  found  in  the  windows  of  the  ancient  cathedrals. 

The  metallic  oxides,  used  in  staining  glass,  are  difficult 
of  fusion  ;  on  which  account,  it  is  necessary  to  mix  them 
with  a  flux,  composed  of  glass,  with  lead  or  borax.  This 
renders  the  oxide  fusible,  at  a  temperature  which  does 
not  injure  its  color  ;  also,  by  enveloping  the  particles,  it 
causes  them  to  adhere  to  the  glass,  and  afterwards  pro- 
tects them  from  the  atmosphere. 

A  very  beautiful  violet,  but  liable  to  turn  blue,  is  made 
from  a  flux,  composed  of  borax  and  flint-glass,  colored 
with  one  sixth  part  of  the  purple  of  Cassius^  precipitated 
from  muriate  of  gold,  by  protomuriite  of  tin. 


ENAMELLING.  257 

A  fine  red  is  made  from  red  oxide  of  iron,  prepared  by 
nitric  acid  and  heat,  mixed  with  a  flux  of  borax,  and  a 
small  proportion  of  red  lead. 

A  yellow,  equal  in  beauty  to  that  produced  by  the  an- 
cients, may  be  made  from  muriate  of  silver,  oxide  of 
zinc,  white  clay,  and  the  yellow  oxide  of  iron,  mixed  to- 
gether, without  any  flux.  A  powder  remains  on  the  sur- 
iace,  after  the  glass  has  been  baked  ;  but  this  is  easily 
cleaned  off. 

Blue  is  produced  by  oxide  of  cobalt,  with  a  flux,  com- 
posed of  fine  sand,  purified  pearlash,  and  red  lead. 

Black  is  produced,  by  mixing  the  composition  for  blue, 
with  the  oxides  of  manganese  and  iron. 

ToiStain  glass  green,  it  may  be  painted  blue,  on  one 
side,  and  yellow^,  on  the  other. 

The  colors,  ground  with  water,  being  laid  upon  the 
glass,  must  be  exposed  to  heat,  under  a  mufile,  so  as  to 
be  heated  equally,  until  the  color  is  melted  upon  the  sur- 
face. To  prevent  the  panes  of  glass  from  bending,  they 
are  placed  upon  a  bed  of  bone-ashes,  of  quicklime,  or  of 
unglazed  porcelain.  A  bed  of  gypsum  has  been  recom- 
mended ;  but  the  sulphuric  acid,  exhaling  fron^j^  it,  is  apt 
to  injure  the  glass. 

Among  ancient  specimens  of  painted  glass,  some  pieces 
have  been  found,  in  which  the  colors  penetrate  through 
the  glass,  so  that  the  figure  appears  in  any  section,  made 
parallel  to  the  surface.  It  is  supposed,  that  such  pieces 
can  only  have  been  made  in  the  manner  of  mosaic,  by  ac- 
cumulating transverse  filaments  of  glass,  of  different  col- 
ors, and  uniting  them  by  heat,  'the  process  being  one  of 
great  labor.  They  are  described  by  Winckelmann,  and 
Caylus,  from  some  specimens  brought  from  Rome. 

Enamelling. — Enamels  are  compositions  of  various 
substances,  which,  when  vitrified  upon  the  surface  of 
opaque  bodies,  communicate  their  colors,  and  produce 
the  effect  of  painting.  Enamels  differ  from  stained  glass, 
as  a  common  picture  differs  from  a  transparency  ;  the 
former  producing  its  effect,  when  viewed  by  reflected, 
and  the  latter  by  transmitted,  light.  Enamels  are  exe- 
cuted upon  the  surface  of  copper,  and  other  metals,  bv 
22* 


258  ARTS  OF  vitrificatAn. 

a  method,  similar  to  painting.  One  coat,  or  color,  often 
requires  to  be  vitrified,  before  another  is  laid  upon  it ; 
and  thus  the  plate,  to  be  enamelled,  is  obliged  to  be  ex- 
posed to  heat,  several  successive  times. 

Transparent  enamels  are  usually  rendered  opaque,  by 
adding  putty,  or  the  white  oxide  of  tin,  to  them.  The 
basis  of  all  enamels  is,  therefore,  a  transparent  and  fusi- 
ble glass.  The  oxide  of  tin  renders  this  of  a  beautiful 
white,  the  perfection  of  which  is  greater,  when  a  small 
quantity  of  manganese  is  likewise  added.  If  the  oxide 
of  tin  be  not  sufficient  to  destroy  the  transparency  of  the 
mixture,  it  produces  a  semi-opaque  glass,  resembling  the 
opal. 

The  metals,  employed  as  coloring  materials,  are,  1. 
Gold.  The  purple  of  Cassius  imparts  a  fine  ruby  tint. 
2.  Silver.  Oxide,  or  phosphate,  of  silver,  gives  a  yellow 
color.  3.  Iron.  The  oxides  of  iron  produce  green,  yel- 
low, and  brown,  depending  upon  the  state  of  oxidizement, 
and  quantity.  4.  Copper.  The  oxides  of  copper  give  a 
rich  green  ;  they  also  produce  a  red,  when  mixed  with 
a  small  proportion  of  tartar,  which  tends,  partially,  to  re- 
duce the»  oxide.  5.  Antimony  imparts  a  rich  yellow. 
6.  Manganese.  The  black  oxide  of  this  metal,  in  large 
quantities,  forms  a  black  glass  ;  in  smaller  quantities,  vari- 
ous shades  of  purple.  7.  Cobalt,  in  the  state  of  oxide, 
gives  beautiful  blues,  of  various  shades  ;  and,  with  the  yel- 
low of  antimony,  or  lead,  it  produces  green.  8.  Chrome 
produces  fine  greens  and  reds,  depending  upon  its  state  of 
oxidizement. 

Artificial  Gems. — The  great  value  of  the  precious 
stones  has  led  to  artificial  imitations  of  their  color  and 
lustre,  by  compositions  in  glass.  In  order  to  approximate, 
as  near  as  possible,  to  the  briUiancy,  and  refractive  power, 
of  native  gems,  a  basis,  called  a  paste,  is  made  from  the 
finest  flint-glass,  composed  of  selected  materials,  combin- 
ed, in  different  proportions,  according  to  the  preference 
of  the  manufacturer.  This  is  mixed  with  metallic  oxides, 
capable  of  producing  the  desired  color.  A  great  num- 
ber of  complex  recipes  are  in  use,  among  manufacturers 
of  these  articles. 


DEVITRIFICATION. REAUMUR's   PORCELAIN.    259 

Devitrification. — It  is  found,  that,  if  certain  kinds  of 
glass  be  exposed  to  heat,  sufficient  to  keep  them  in  a  soft 
state,  for  some  hours,  and  are  suffered  to  cool,  gradually, 
they  lose  their  transparency,  and  pass  into  the  state  of  an 
opaque  substance,  of  a  grayish  white  color.  M.  Dartri- 
gues,*  who  has  examined  the  cause  of  this  change,  as- 
serts, that  it  is  owing  to  a  real  crystallization  of  the  vitreous 
siHcate.  Common  bottle-glass  is  most  easily  changed,  in 
this  manner  ;  while  those  varieties,  which  contain  neither 
lime,  nor  alumina,  are  the  most  difficult  to  devitrify.  In 
all  cases,  glass,  which  has  undergone  this  change,  requires 
a  stronger  heat  to  melt  it,  than  before. 

Reaumur^s  Porcelain. — It  has  been  frequently  observ- 
ed, that,  during  the  anneahng  of  green  glass,  some  parts  of 
it  become  white,  and  opaque.  M.  Reaumur  made  experi- 
ments on  this  apparent  devitrification  of  glass,  and  found 
it  was  owing  to  the  alkali  flying  off,  by  the  too  long  con- 
tinuance, or  too  great  degree,  of  the  heat,  and  that  the 
opaque,  changed  glass,  had  acquired  the  quality  of  bear- 
ing sudden  transitions  of  heat  and  cold,  as  well  as  the 
best  porcelain. 

For  the  purpose  of  making  vessels,  of  this  kind,  com- 
mon bottle-glass  is  chosen,  and  blown  into  the  proper 
form.  The  vessfel  is  then  to  be  filled  to  the  top,  with  a 
mixture  of  white  sand  and  gypsum,  and  is  set  in  a  large 
crucible,  upon  a  quantity  of  the  same  mixture,  with  which 
the  glass  vessels  must  also  be  surrounded,  and  covered 
over,  and  the  whole  pressed  down,  rather  hard.  The 
crucible  is  then  to  be  covered  with  a  Hd,  the  junctures 
well  luted,  and  put  into  a  potter's  kiln,  where  it  remains, 
during  the  whole  time  that  the  pottery  is  baking  ;  after 
which,  the  glass  will  be  found  changed  into  a  milk-white 
porcelain. 

An  imitation  of  porcelain,  which  is  lately  introduced 
into  our  shops,  and  which  combines  whiteness  with  a 
beautiful  semi-transparency,  is  made  of  flint-glass,  con- 
taining a  portion  of  white  arsenic,  on  which  its  opacity 
depends. 

♦Journal  de  Physique,  1804.— Thenard,  Chimie,  ii.  473 


260  ARTS   OF  VITRIFICATION. 

Crystallo  Ceramie. — This  name  is  given  loan  elegant) 
but  difficult,  species  of  manufacture,  in  which  medallions, 
portraits,  and  other  subjects,  executed  in  an  opaque  mate- 
rial, are  enclosed,  or  encrusted,  with  glass.  This  art  was 
first  attempted,  by  enclosing,  in  glass,  smafi  figures,  made 
of  a  peculiar  kind  of  clay  ;  but  these  experiments  were 
only  in  few  instances  successful,  owing  to  the  unequal  ex- 
pansion and  contraction  of  the  two  substances,  and  theii 
consequent  fracture.  More  recently,  a  composition  has 
been  employed,  for  the  opaque  figure,  which  is  less  liable 
to  these  accidents.  It  is  necessary,  that  the  substance, 
employed  in  these  devices,  should  be  less  fusible  than 
glass,  incapable  of  generating  air,  and,  at  the  same  time, 
susceptible  of  expansion  and  contraction,  as  the  glass 
becomes  hot  or  cold.  The  ornamental  figures  are  intro- 
duced into  the  glass  while  hot,  and  thus  become  incorpor- 
ated with  it. 

Glass  Thread. — The  great  ductility  of  glass  is  one 
of  its  most  remarkable  properties.  When  heated  to  a 
sufficient  degree,  i't  may  not  only  be  moulded,  into  any 
possible  form,  with  the  utmost  facility,  but  it  can  be  drawn 
out  into  the  finest  fibres.  The  method  of  spinning  glass 
is  very  simple.  The  operator  holds  a  piece  of  glass  over 
the  flame  of  a  lamp,  w^ith  one  hand  ;  he  then  fixes  a  hook 
to  the  melted  mass,  and,  by  withdrawing  it,  obtains  a  thread 
of  glass,  attached  to  the  hook.  The  hook  is  then  fixed  in 
the  circumference  of  a  cylindrical  drum,  which  can  be 
turned  round  by  the  hand  ;  and  a  rapid,  rotary  motion 
being  given  to  the  drum,  the  glass  is  drawn  in  the  finest 
threads,  from  the  fluid  mass,  and  coiled  round  the  cylin- 
drical circumference.  M.  Reaumur  supposed,  with  great 
reason,  that  the  flexibility  of  glass  increased  with  the  fine- 
ness of  the  threads,  and  he  therefore  conjectured,  that,  if 
they  were  drawn  to  a  sufficient  degree  of  fineness,  they 
might  be  used  in  the  fabrication  of  stufl^s.  He  succeeded 
in  making  them  as  fine  as  a  spider's  web  ;  but  he  was  nev- 
er able  to  obtain  them  of  a  sufficient  length,  when  their  di- 
ameter was  so  much  reduced.  The  circumference  of 
these  threads  is  generally  a  flat  oval,  about  three  or  four 
times  as   broad  as  it  is  thick.      By  using  opaque   and 


REMARKS  261 

transparent  glass,  of  different  colors,  artists  have  been 
able  to  produce  many  beautiful  ornaments.  M.  Bonnet, 
and  others,  have  succeeded  in  obtaining  glass  fibres,  of 
such  fineness  and  flexibility,  af  to  admit  of  being  woven 
into  cloth,  of  a  very  brilliant,  silvery  appearance. 

Remarks. — Pure  glass  possesses  the  remarkable  prop- 
erty, of  sufi:ering  no  change  by  the  application  of  an  intense 
heat.  The  effect  of  great  heats  is  only  to  melt  the  glass, 
or  to  dissipate  it  in  vapor  ;  but,  as  long  as  any  of  the  glass 
remains,  it  still  preserves  its  transparency,  and  other  dis- 
tinguishing properties. 

Of  all  the  solid  substances,  whose  expansibility  has 
been  accurately  examined,  glass  possesses  the  property 
of  being  least  affected  by  heat  or  cold.  Its  expansion, 
according  to  General  Roy,  with  an  increase  of  heat,  equal 
to  one  hundred  and  eighty  degrees  of  Fahrenheit's 
thermometer,  is  only  0.000776,  while  that  of  platina  is 
0.000S56,  and  that  of  hammered  zinc,  0.003011.  On 
account  of  this  property,  glass  is  peculiarly  fitted  for  con- 
taining fluids,  whose  expansions  are  under  examination,  as 
its  own  change  of  form  may,  in  ordinary  cases,  be  neglec- 
ted. For  the  same  reason^  it  is  better  than  any  other 
substance,  for  the  simple  pendulum  of  a  clock. 

The  invention  of  glass  seems  to  have  been  extremely 
ancient,  and  some  curious  specimens  are  found,  in  the  sar- 
cophagi of  Egyptian  mummies.  Glass  windows  appear 
not  to  have  been  in  use,  among  the  Romans  of  the  Augus- 
tan age  ;  though  vessels  and  plates  of  glass  are  found  at 
Herculaneum,  and  Pompeii.  Most  of  the  important  im- 
provements, in  the  manufacture  of  this  substance,  have 
been  made  by  the  moderns. 

W^RKs  OF  Reference. — Parkes's  Chemical  Essays,  8vo.  voL 
ii.; — LoYSEL,  Essai  sur  VArt  de  la  Verrerie,  8\'o.  1800; — Brog- 
NiART,  Art  de  V Emailleur,  Annales  de  Chimie,  torn.  ix.  and  other 
works  ; — Franklin  Journal,  v.  80  ; — Article  Glass  in  Rees'  Cyclope- 
dia, and  in  the  Edinburgh  Encyclopedia  ; — Lardxer's  Cabinet  Cy- 
clopedia, 12mo.  vol.  xxvi ; — Chaptal,  Chimie  Appliquee  aux  Arts, 
4  vols.  8vo.  1806  ; — Gray's  Operative  Chemist,  8vo.  1828; — Thex- 
ARD,  Traite  de  Chimie,  vol.  ii. ; — Brande's  Chemistry  ; — Beck- 
man's  History  of  Inventions,  4  Tols.  8vo.  translated  1797; — Works  of 
Neri,  Blancourt,  Kunckbi.,  Reaumur,  &c. 


262  ARTS   OF  INDURATION  BY  HEAT. 

CHAPTER  XXII. 

ARTS  OF   INDURATION  BY  HEAT. 

Brickrf,  Pressed  Bricks,  Tiles,  Terra  Cotta,  Crucibles,  Pottery,  Opera- 
tions, Stone  Ware,  White  Ware,  Throwing,  Pressing,  Casting, 
Burning,  Printing,  Glazing,  China  Ware,  European  Porcelain, 
Etruscan  Vases. 

Common  clay,  with  its  varieties,  consisting  essentially 
of  alumina  and  silica,  also,  the  artificial  imitations  of  clay, 
into  which  these  earths  enter,  possess  properties,  adapted 
to  render  them  highly  useful  in  the  arts.  When  mixed 
with  water,  they  form  a  ductile  and  tenacious  paste,  ca- 
pable of  being  moulded  into  various  forms,  and  of  acquir- 
ing, when  exposed  to  the  heat  of  a  furnace,  a  durable 
and  stony  hardness.  These  compounds  are  used  in  dif- 
ferent states,  to  form  the  materials,  both  for  the  largest 
structures,  and  the  most  delicate  ornaments  ;  and  they 
are  surpassed  by  few  substances,  in  the  power  of  resisting 
the  effects  of  exposure  and  time.  Bricks,  tiles,  terra- 
cotta, pottery,  and  porcelain,  are  the  most  noticeable  pro- 
ducts of  the  branch  of  industry,  in  the  operations  of  which 
indurated \:lay  is  the  material." 

Bricks. — The  use  of  bricks,  in  building,  may  be  traced 
to  the  earhest  ages,  and  they  are  found  among  the  ruin- 
of  almost  every  ancient  nation.  The  walls  of  Babylon, 
some  of  the  ancient  structures  of  Egypt,  and  Persia,  the 
walls  of  Athens,  the  Rotunda  of  the  Pantheon,  the  Tem- 
ple of  Peace,  and  the  Thermae,  at  Rome,  were  all  of  brick. 
The  earliest  bricks  were  dried  in  the  sun,  and  were  never 
exposed  to  great  heat,  as  appears  from  the  fact,  that  thev 
contain  reeds  and  straws,  upon  which  no  mark  of  burning 
is  visible.  These  bricks  owe  their  preserviation  to  the 
extreme  dryness  of  the  climate,  in  which  they  have  re- 
mained ;  since  the  earth,  of  which  they  are  made,  often 
crumbles  to  pieces,  when  immersed  in  water,  after  having 
kept  its  shape  for  more  than  two  thousand  years.      This 


PRESSED  BRICKS.  263 

is  the  case,  with  some  of  the  Babylonian  bricks,  with  in- 
scriptions in  the  arrow-headed  character,  which  have  been 
brought  to  this  country.  The  ancients,  however,  at  a  later 
period,  burnt  their  bricks  ;  and  it  is  these,  chiefly,  which 
remain  at  the  present  day.  The  antique  bricks  were 
larger  than  those  employed  by  the  moderns,  and  were  al- 
most universally  of  a  square  form.  Besides  bricks  made 
of  clay,  the  ancients  also  employed  a  kind  of  factitious 
stone,  composed  of  a  calcareous  mortar.* 

Modern  bricks  receive  their  hardness  from  exposure  to 
heat,  in  the  process  of  burning.  The  common  clay,  of 
which  they  are  made,  consists  of  a  mixture  of  argillaceous 
earth,  and  sand.  Most  of  our  common  clays  contain,  also, 
oxide  of  iron,  which  causes  the  bricks  to  turn  red,  in  burn- 
ing, l^ure  clays  become  white  in  the  furnace,  such  as 
that  of  which  pipes  are  made,  and  common  crockery-ware. 
Clay,  after  it  is  taken  from  the  earth,  requires  to  be 
thoroughly  mixed,  incorporated,  and  mellowed,  before  it 
is  fit  for  the  manufacture  of  bricks.  For  this  purpose,  a 
is  to  be  dug  in  the  summer,  or  autumn,  and  exposed  to  the 
influence  of  the  frost,  through  the  winter.  It  should  be 
worked  over  repeatedly,  whh  the  spade,  and  not  made  into 
bricks,  till  the  ensuing  spring,  previously  to  which,  it  is 
well  tempered,  either  by  treading  it,  with  oxen,  or  by  a 
horse-mill,  till  it  is  reduced  to  a  tough,  homogeneous 
paste.  In  proportion  to  the  labor  bestowed  on  this  pro- 
cess, the  bricks  become  solid,  hard,  and  strong.  The 
clay,  after  being  thus  prepared,  is  forced  into  moulds,  to  re- 
ceive the  shape  of  bricks,  and  afterwards  dried  in  the  sun. 

Pressed  bricks^  which  are  used  to  form  the  facing  of 
walls,  in  the  better  kinds  of  structures,  are  finished  in  a 
machine.  The  roughness,  and  change  of  form,  to  which 
common  bricks  are  liable,  is  owing,  in  part,  to  the  evap- 
oration of  a  portion  of  the  water,  which  the  clay  contains. 
To  remedy  the  difiiculty,  arising  from  this  cause,  the 
bricks,  after  being  moulded,  in  the  common  manner, 
are  exposed  to  the  sun,  till  they  are  nearly  dried  ;  retain- 
ing, however,  sufficient  plasticity,  to  be  still  capable  of  a 

*Some  travellers  have  even  advanced  an  opinion,  that  the  Py  amijg 
of  Egypt  are  constructed  with  an  artificial  stone. 


264  ARTS    OF   INDURATION  BY   HEAT. 

slight  change  of  form.  In  this  state,  they  are  placed  in 
an  iron  mould,  and  subjected  to  a  strong  pressure,  by 
which  they  become  regular  in  shape,  and  very  smooth. 
A  machine  usually  contains  a  number  of  moulds,  arranged 
in  a  circle,  or  otherwise ;  so  that  the  power  is  applied  to 
them  in  succession,  and  the  bricks  pressed  with  rapidity. 

The  burning  of  bricks  is  commonly  performed,  in  this 
country,  by  forming  them  into  large,  square  piles,  de- 
nominated clamps,  or,  with  us,  kilns,  having  flues,  or 
cavities,  at  the  bottom,  for  the  insertion  of  the  fuel,  and 
interstices  between  the  bricks,  for  the  fire  and  hot  air  to 
penetrate.  A  fire  is  kindled  in  these  cavities,  and  grad- 
ually increased,  for  the  first  twelve  hours,  after  which,  it 
is  kept  up,  at  a  uniform  height,  for  several  days  and 
nights,  till  the  bricks  are  sufiiciently  burned.  Much  care 
and  experience  are  necessary,  in  regulating  the  fire,  since 
too  much  heat  vitrifies  them,  and  too  little,  leaves  them 
soft  and  friable.  In  some  places,  the  burning  of  bricks 
is  conducted  in  permanent  kilns,  erected  for  the  purpose. 

Tiles. — Tiles  are  plates  ofburnt  clay,  resembling  bricks, 
in  their  composition  and  manufacture,  and  used  for  the 
covering  of  roofs.  They  are  necessarily  made  thicker 
than  slates  or  shingles,  and  thus  impose  a  greater  weight 
upon  the  roofs.  Their  tendency  to  absorb  water  pro- 
motes the  decay  of  the  wood-work  beneath  them.  Tiles 
are  usually  shaped  in  such  a  manner,  that  the  edge  of 
one  tile  receives  the  edge  of  that  next  to  it,  so  that  water 
cannot  percolate  between  them.*  Tiles,  both  of  burnt 
clay,  and  marble,  were  used  by  the  ancients  ;  and  the  for- 
mer continue  to  be  employed  in  various  parts  of  Europe. 
Floors,  made  of  flat  tiles,  are  used  in  many  countries, 
particularly  in  Italy. 

Terra  Cotta. — The  Italian  name,  terra-cotta,  in  French, 
terre-cuite,  in  its  most  general  sense,  implies  clay,  in- 
durated by  heat.  In  the  arts,  however,  its  use  seems  to 
be  restricted  to  the  finer  clays,  in  which  ornamental  de- 
signs have  been  executed,  both  by  the  ancients  and  mod- 
erns.    Not  only  vases,  but  imhations  of  sculpture,  and 

*  For  different  forms  of  tiles,  used  at  Florence,  Trieste,  &c.,  see 
Cadoll's  Journey  in  Italy,  and  Carniola,  Plate  X. 


CRUCIBLES. POTTERY.  205 

architectural  decorations,  are  successfully  made,  froir 
this  material.  Among  other  things,  a  complete  restoia- 
tion  of  the  Choragic  monument  of  Lysicrates,  at  Athens, 
has  been  made  from  terra-cotta,  in  the  court  of  the  Lou 
vre,  at  Paris.  From  the  facihty  with  which  it  is  mould- 
ed into  any  form,  this  substance  would  be  of  great  use  in 
architecture,  were  it  not  for  the  unequal  shrinking  of  the 
clay,  from  heat,  and  the  difficulty  of  preserving,  accurate- 
ly, the  original  proportions. 

Crucibles. — Crucibles,  melting-pots,  and  other  vessels, 
intended  for  use  in  the  furnace,  require  to  be  made  of 
substances,  which  sustain  a  high  temperature,  without 
fusion.  When  they  are  made  of  about  one  part  of  pure 
clay,  mixed  with  three  of  sand,  and  slowly  dried,  and 
annealed,  they  are  found  to  bear  a  great  heat,  and  will  re- 
tain mo^t  of  the  metals  which  are  melted  for  use  in  the 
arts.  Such  crucibles,  however,  are  hable  to  be  acted 
upon  and  destroyed,  at  high  temperatures,  if  the  metals 
are  suffered  to  become  oxidized,  or  if  saline  fluxes  are 
used.  To  prevent  this  accident,  some  crucibles  are 
made  entirely  of  clay,  which  is  burnt,  coarsely  powdered, 
and  mixed  with  fresh  clay.  These  are  found  very  re- 
fractory in  the  furnace.  Crucibles  are  also  made  of  plain 
Stourbridge  clay,  of  Wedgewood's  ware,  of  graphite,  and 
of  platina. 

Pottery. — In  manufactures  of  vessels,  from  argilla- 
ceous compounds,  the  different  degrees  of  beauty,  and 
costliness,  depend  upon  the  quahty  of  the  raw  material 
used,  and  upon  the  labor  and  skill,  expended  in  the  op- 
eration. The  cheapest  products  of  the  art,  are  those 
made  of  common  clay,  similar  to  that  of  which  bricks  are 
formed,  and  which,  from  the  iron  it  contains,  usually  turns 
red,  in  burning.  Next  to  this,  is  the  common  crockery- 
ware,  formed  of  the  purer  and  whiter  clays,  in  which 
iron  exists,  only  in  minute  quantities.  Porcelain,  which 
is  the  most  beautiful  and  expensive  of  all,  is  formed 
only  from  argillaceous  minerals,  of  extreme  dehcacy, 
united  with  sihcious  earths,  capable  of  communicating  to 
them  a  semi-transparency,  by  means  of  its  vitrification. 

Clay,  although  it  is  a  compound  body,  and  possesses 
II.  23  XII. 


266  ARTS   OF   INDURATION  BY   HEAT. 

more  silica  than  alumina,  neverlneless,  derives  character? 
from  the  latter,  which  abundantly  distinguish  it  from  mm- 
erals,  which  are  more  purely  silicious.  The  processes  of 
its  manufacture  are,  in  most  respects,  the  reverse  of  those 
applied  to  glass,  that  substance  being  softened  by  heat, 
and  wrought  at  a  high  temperature,  whereas,  the  clay  's 
wrought  while  cold,  and  afterwards  hardened  by  heat. 

Operations. — Though  the  various  kinds  of  pottery 
and  porcelain  differ  from  each  other,  in  the  details  of 
their  manufacture,  yet  there  are  certain  general  principles, 
and  processes,  which  are  common  to  them  all.  The  first 
belongs  to  the  preparation  of  the  clay,  and  consists  in  di- 
viding and  washing  it,  till  it  acquires  the  requisite  fine- 
ness. The  quahty  of  the  clay  requires  the  intermixture 
of  a  certain  proportion  of  sihcious  earth,  the  effect  of 
which  is  to  increase  its  firmness,  and  render  it  less  hable 
to  shrink  and  crack,  on  exposure  to  heat.  In  common 
clay,  a  sufficient  quantity  of  sand  exists,  in  a  state  oi 
natural  mixture,  to  answer  this  purpose.  But  in  the  finer 
kinds,  an  artificial  admixture  of  silica  is  necessary.  The 
paste,  which  is  thus  formed,  is  thoroughly  beaten  and 
kneaded,  to  render  it  ductile,  and  to  drive  out  the  air. 
It  is  then  ready  to  receive  its  form.  The  form  of  the 
vessel,  intended  to  be  made,  is  given  to  the  clay,  either 
by  turning  it  on  a  wheel,  or  by  casting  it  in  a  mould. 
When  dry,  it  is  transferred  to  the  oven,  or  furnace,  and 
there  burnt,  till  it  acquires  a  sufficient  degree  of  hardness, 
for  use.  Since,  however,  the  clay  is  still  porous,  and, 
of  course,  penetrable  to  water,  it  is  necessary  to  glaze  it. 
This  is  done,  by  covering  the  surface  with  some  vitrifiable 
substance,  and  exposing  it,  a  second  time,  to  heat,  until 
this  substance  is  converted  into  a  coating  of  glass. 

In  the  coarse  earthen  ware,  which  is  made  of  common 
clay,  the  clay,  after  being  mixed  and  kneaded,  until  it 
has  acquired  the  proper  ductility,  is  transferred  to  a  sort 
of  revolving  table,  called  the  wheel.  A  piece  of  clay,  of 
sufficient  size,  being  placed  liTthe  centre  of  this  table,  a 
rotary  motion  is  communicated  to  it,  by  the  feet.  The 
potter  then  begins  to  shape  it,  with  his  hands,  which  are 
previously  wet,  to  prevent  its  adhering  to   the   fingers 


STONE-WARE. WHITE-WARE.  267 

The  rotary  motion  gives  it  a  circular  form,  and  it  is 
gradually  wrought  up  to  the  intended  shape,  a  tool  being 
occasionally  used,  to  assist  the  finishing.  The  vessels 
are  now  set  aside,  to  dry  ;  after  which,  they  are  baked 
in  the  oven,  or  kiln.  The  glazing,  of  this  kind  of  pottery, 
is  given  by  metallic  oxides,  which  vitrify  at  a  low  heat. 
A  yellow  glazing  is  communicated,  by  the  oxide  of  lead  ; 
black,  by  the  oxide  of  manganese  ;  and  white,  by  the 
oxide  of  tin.  Unglazed  ware  is  porous,  and  permeable 
to  water,  as  is  seen  in  common  flower-pots,  and  coolers. 

Stone  Ware. — The  kinds  of  pottery,  denominated 
stone-ware,  may  be  formed  of  the  clays,  which  are  used 
for  other  vessels,  by  applying  to  them  a  much  greater 
degree  of  heat,  the  effect  of  which  is,  to  increase,  very 
much,  their  strength  and  solidity.  These  vessels  do  iiot 
require  to  be  glazed,  with  any  metallic  oxides,  but  afibrd 
the  material  of  their  own  glazing,  by  a  vitrification  of  their 
surface.  When  the  furnace,  in  which  they  are  burnt,  has 
arrived  at  its  greatest  heat,  a  quantity  of  muriate  of  soda, 
or  common  salt,  is  thrown  into  the  body  of  the  kiln. 
The  salt  rises  in  vapor,  and  envelopes  the  hot  ware,  and, 
by  the  combination  of  its  alkali  with  the  silicious  particles 
on  the  surface  of  the  ware,  a  perfect  vitrification  is  pro- 
duced. This  glazing,  consisting  of  an  earthy  glass,  is  in- 
soluble in  most  chemical  agents,  and  is  free  from  the  ob- 
jections, to  which  vessels,  glazed  with  lead,  are  liable, 
that  of  communicating  an  unwholesome  quality  to  liquids 
contained  in  them,  by  the  solution  of  the  lead  in  common 
acids,  which  they  frequently  contain. 

White  Ware. — The  better  sorts  of  earthen  ware  are 
made  of  white  clay,  or  of  clay  containing  so  little  oxide 
of  iron,  that  it  does  not  turn  red  in  burning,  but,  on  the 
contrary,  improves  its  whiteness  in  the  furnace.  This 
kind,  commonly  called  pipe  clay,  is  found  very  pure  in 
Devonshire,  and  Dorsetshire,  in  England.  In  the  manu- 
factory of  Mr.  Wedgewood,  to  whose  industry  and  in- 
genuity the  pubHc  are  indebted,  for  some  of  the  finest 
specimens  of  the  art,  the  clay  is  prepared,  by  first  bring- 
ing it  to  a  state  of  minute  division,  by  the  aid  of  machine- 
ry.    This  machinery  consists  of  a  series  of  iron  blades, 


268  ARTS   OF   INDURATION   BY  HEAT. 

or  knives,  fixed  to  an  upright  axis,  and  made  to  revolve 
in  a  cylinder,  and  intersecting,  or  passing  between,  anoth- 
er set  of  blades,  which  are  fixed  to  the  cylinder.  The 
clay,  by  the  continual  intersection  of  these  blades,  is 
minutely  divided,  and,  when  sufficiently  fine,  is  transferred 
to  a  vat.  It  is  here  agitated,  with  water,  until  it  assumes 
the  consistence  of  a  pulp,  so  thin,  that  the  coarser  or 
stony  particles  can  subside  to  the  bottom,  after  a  little 
rest,  while  the  finer  clay  remains  in  suspension.  This 
last  is  poured  ofi:',  and  suffered  to  subside,  after  which  it 
is  passed  through  sieves,  of  different  fineness,  and  be- 
comes sufficiently  attenuated  for  use. 

To  this  clay  is  added  a  certain  quantity  of  flint,  re- 
duced to  powder,  by  heating  it  red  hot,  and  throwing  it 
into  cold  water,  to  diminish  the  cohesion  of  its  parts. 
Afterwards,  it  is  pounded  by  machinery,  ground  in  a  mill, 
sifted,  and  washed,  precisely  as  the  clay  is  treated,  and 
made  into  a  similar  pulp.  In  this  state,  the  two  ingredi- 
ents are  intimately  mixed  together,  in  such  quantities, 
that  the  clay  bears  to  the  flint  the  proportion  of  about 
five  to  one. 

The  object  of  adding  flint  to  the  clay  is  two-fold.  It 
lessens  the  shrinking  of  the  clay,  in  the  fire,  and  thus  ren- 
ders it  less  liable  to  warp  and  crack,  in  the  burning.  At 
the  same  time,  by  its  partial  fusion,  it  communicates  to 
the  ware  that  beautiful  translucency,  which  is  so  much 
admired  in  porcelain,  and  of  which  the  simple  clay-wares 
are  destitute. 

The  fine  pulp  of  flint  and  clay,  being  intimately  mixed, 
is  then  exposed  to  evaporation,  by  a  gentle  heat,  until 
the  superfluous  water-  is  dissipated,  and  the  mass  reduced 
to  a  proper  consistency  to  work.  To  produce  a  unifor- 
mity, in  the  thickness  of  the  material,  it  is  taken  out,  in 
successive  pieces,  which  are  repeatedly  divided,  struck, 
and  pressed  together,  till  every  part  becomes  blended  with 
the  rest. 

Throioing. — The  formation  of  circular  vessels  is  done 
by  the  process  called  throwing,  performed  on  the  potter's 
wheel,  in  the  manner  already  described  ;  except  that,  in 
large  manufactories,  the  wheel  is  not  turned  by  the  oper- 


PRESSING. CASTING. BURNING.  269 

ator  himself,  but  by  an  assistant,  or  a  steam-engine.  The 
handles,  and  similar  appendages,  are  made,  by  forcing 
the  clay  with  a  piston,  through  an  aperture,  of  the  size 
and  shape  which  it  is  desired  to  produce.  When  formed, 
the  handles  are  cemented  to  the  ware,  by  a  thin  mixture 
of  the  clay  with  water,  which  the  workmen  call  slip. 
The  vessels,  when  complete,  are  dried,  with  a  gradual 
heat,  in  a  room,  heated  to  eighty  or  ninety  degrees,  and, 
after  being  smoothed  from  any  irregularities  of  surface, 
they  are  conveyed  to  the  kiln. 

Pressing. — The  only  vessels  which  can  be  made  in 
the  wheel,  or  lathe,  are  those  of  a  circular  form.  When 
the  form  is  different,  the  vessel  must  be  made,  either  by 
press-work,  or  casting.  The  press-work  is  executed  in 
moulds,  made  of  plaster  of  Paris,  one  half  the  figure  be- 
ing on  one  side  of  the  mould,  and  the  other  half,  on  the 
other  side.  These  fit  accurately  together.  The  clay  is 
first  made  into  two  flat  pieces,  of  the  thickness  of  the  ar- 
ticles ;  one  of  these  is  pressed  into  one  side  of  the  mould, 
and  the  other  into  the  other  side.  The  superfluous  clay 
being  cut  away,  the  two  sides  of  the  mould  are  brought 
together,  to  unite  the  two  halves  of  the  vessel.  The 
mould  is  now  separated  from  the  clay,  and  the  article  is 
finished,  as  to  form.  When  dry,  it  is  completed  by  the 
addition  of  handles  or  other  parts,  belonging  to  it.  All 
vessels,  of  an  oval  form,  or  which  have  flat  sides,  may 
be  made  in  this  way. 

Casting. — In  the  third  method,  called  castings  the  clay 
is  used  in  the  state  of  pulp,  sufficiently  thin  to  flow.  It 
is  poured  into  moulds,  made  o{  plaster,  by  which  the  su- 
perfluous water  being  rapidly  absorbed,  the  clay  is  depos- 
ited, and  acquires  sufficient  solidity  to  preserve  the  shape 
communicated  by  the  mould.  It  is  then  taken  out,  and 
dried,  and  transferred  to  the  kiln. 

Burning. — All  vessels,  when  formed,  are  in  a  very 
tender  and  frangible  state,  before  they  are  submitted  to 
the  action  of  fire.  The  burning,  or  hardening,  is  per 
formed  in  kilns  ;  and  to  preserve  the  ware  from  injury, 
it  is  enclosed  in  cases,  or  boxes,  of  burnt  clay,  called 
saggarsy  m  which  it  is  heated  red  hot,  by  the  flame  cir 
23* 


270  ARTS   OF  INDURATION  BY  HEAT. 

culating  among  the  cases.  The  fire  is  kept  up,  from  twen 
ty-four  to  forty-eight  hours,  and  the  saggars  suffered  to 
cool,  before  they  are  removed.  The  ware  is  then  found 
to  have  acquired  great  hardness,  and  is  converted  into  a 
dry,  sonorous,  and  extremely  bibulous,  solid.  In  this  state, 
it  is  called  the  biscuit.  It  adheres  strongly  to  the  tongue, 
and  absorbs  water  in  such  quantities,  that  vessels,  in  this 
state,  are  used  as  coolers,  being  kept  saturated  with  wa- 
ter, which,  as  it  passes  constantly  to  the  outer  surface, 
generates  cold,  by  its  evaporation. 

Printing. — When  colors,  or  designs,  are  to  be  im- 
pressed upon  the  vessels,  it  is  necessary,  in  most  cases, 
that  it  should  be  done,  before  the  ware  is  glazed.  In 
China,  the  drawings  on  the  surface  of  porcelain,  and  oth- 
er wares,  are  executed  by  hand,  with  the  pencil ;  and  the 
same  method  is  pursued  in  Europe,  in  elaborate  pieces  of 
workmanship.  But,  in  the  common  figured  white-ware, 
the  designs  are  first  engraved  upon  copper,  and  an  im- 
pression taken  on  thin  paper,  in  the  common  mode  of 
copperplate-printing,  except  that  the  color  is  a  metallic 
oxide.  The  paper  is  then  moistened,  apphed  closely  to 
the  biscuit,  and  rubbed  on  ;  by  w^hich  process,  the  color- 
ing matter  is  absorbed,  in  consequence  of  the  porosity  of 
the  earthen  material.  The  paper  is  then  w^ashed  off, 
leaving  the  printed  figure  transferred  to  the  sides  of  the 
vessel.  Blue  and  white  ware  is  printed  with  oxide  of 
cobalt,*  and  a  black  color  is  imparted,  by  an  admixture 
with  the  oxides  of  n\anganese  and  iron. 

Glazing. — To  prevent  the  penetration  of  fluids,  it  is 
necessary,  that  vessels  should  be  glazed,  or  covered,  with 
a  vitreous  coating.  The  materials  of  common  glass 
would  afford  the  most  perfect  glazing  to  crockery-ware, 
were  it  not  that  the  ratio  of  its  expansion  and  contrac- 
tion, is  not  the  same  with  that  of  the  clay  ;  so  that  a 
glazing  of  this  sort  is  liable  to  cracks  and  fissures,  when 
exposed  to  changes  of  temperature.  A  mixture,  of  equal 
parts  of  oxide  of  lead  and  ground  flints,  is  found  to  be  a 

*  Mr.  Parkes  informs  us,  that  such  improvements  are  made  in  the 
manufacture  of  this  article,  that  the  Chinese  potters  are  now  supplied 
from  England,  with  all  the  cobalt  they  consume. 


CHINA-WARE. EUROPEAN  PORCELAIN.  271 

durable  glaze,  for  the  common  cream-colored  ware,  and 
is  generally  used  for  that  purpose.  These  materials  are 
first  ground  to  an  extremely  fine  powder,  and  mixed  with 
water,  to  form  a  thin  liquid.  The  ware  is  dipped  into 
this  fluid,  and  drawn  out.  The  moisture  is  soon  absorb- 
ed by  the  clay,  leaving  the  glazing  particles  upon  the  sur- 
face. These  are  afterwards  melted,  by  the  heat  of  the  kiln, 
and  constitute  a  uniform  and  durable  vitreous  coating. 

The  English  and  French  manufacturers  find  it  neces- 
sary to  harden  their  vessels,  by  heat,  or  to  bring  them  to 
the  state  of  biscuit,  before  they  are  glazed  ;  but  the  com- 
position used  by  the  Chinese  resists  water,  after  it  has 
been  once  dried  in  the  air,  so  as  to  bear  dipping  in  the 
glazing  Hquid,  without  injury.  This  gives  them  a  great 
advantage,  in  the  economy  of  fuel. 

China  Ware. — The  Chinese  porcelain  excels  other 
kinds  of  ware,  in  the  delicacy  of  its  texture,  and  the  par- 
tial transparency  which  it  exhibits,  when  held  against  the 
hght.  It  h^s  been  long  known  and  manufactured,  by  the 
Chinese,  but  has  never  been  successfully  imitated,  in  Eu- 
rope, until  within  the  last  century.  In  China,  porcelain 
is  made  by  the  union  of  two  earths,  to  which  they  give 
the  name  o^ petuntze,  and  kaolin^  the  former  of  which  is 
fusible  in  the  furnace,  the  latter,  not.  Both  these  earths  are 
varieties  of  feldspar,  the  kaolin  being  feldspar,  in  a  state  of 
decomposition,  and  which  is  rendered  infusible,  by  having 
lost  the  small  quantity  of  potass,  w^hich  originally  entered 
into  its  composition.  The  petuntze  is  feldspar,  undecom- 
posed.  These  earths  are  reduced  to  an  impalpable  pow- 
der, by  processes,  similar  to  those  already  described,  and 
intimately  blended  together.  When  exposed  to  a  strong 
heat,  the  petuntze  partially  melts,  and,  enveloping  the  in- 
fusible kaolin,  communicates  to  it  a  fine  serai-transparen- 
cy. The  glazing  is  produced  by  the  petuntze  alone,  ap- 
plied in  minute  powder  to  the  ware,  after  it  is  dry. 

European  Porcelain. — Since  the  nature  of  the  Chi- 
nese earths  has  been  understood,  materials,  nearly  of  the 
same  kind,  have  been  found,  in  different  parts  of  Europe, 
and  the  manufacture  of  porcelain  has  been  carried  on  in 
several  countries,  but  particularly  at  Sevres,  in  France, 


2"?2  AP/a   OF  INDURATION  BY  HEAT. 

^•ith  great  success.      The  European  porcelains,  in  the 
elegance  and  variety  of  their  forms,  and  the  beauty  of 
the  designs  which  are  executed   upon   them,   excel  the 
manufactures  oi  the  Chinese.     But  the  Oriental  porcelain 
has  not  yet  been  equalled,  in  hardness,  strength,  durabili 
ty,  and  the   permanency  of  its   glaze.      Several   of  the 
processes,  which  are  successfully  practised  by  the  Chi 
nese,  remain  still  to  be  learnt  by  Europeans.      The  man 
ufacturers  in  Saxony  are  said  to  have  approached  mos^ 
nearly,  in  their  products,  to  the  character  of  the  Asiatic 
porcelain. 

The  porcelain  earths  are  found  in  various  parts  of  the 
United  States,  and  will,  doubtless,  hereafter  constitute 
the  material  of  important  manufactures. 

The  finer  and  more  costly  kinds  of  porcelain  derive 
their  value,  not  so  much  from  the  quality  of  their  mate- 
rial, as  from  the  labor  bestowed  on  their  external  decora- 
tion. When  the  pieces  are  separately  painted  by  hand, 
with  devices  of  different  subjects,  their  value,  as  speci- 
mens of  art,  depends  upon  the  size  of  the  piece,  the  num- 
ber and  brilliancy  of  the  colors  employed,  and,  more 
especially,  upon  the  skill  and  finish  exhibited  by  the  ar- 
tist, in  the  design.  The  manual  part  of  the  operation 
consists,  in  mixing  the  coloring  oxide  with  a  fluid  medi- 
um, commonly  an  essential  oil,  and  applying  it  with  cam- 
els' hair  pencils.  The  colors  used  are  the  same,  as  those 
employed  in  other  kinds  of  enamelling.  When  one  color 
requires  to  be  laid  over  another,  this  is  performed  by  a 
second  operation  ;  and  it  often  happens,  that  a  piece  of 
porcelain  has  to  go  into  the  enamel-kiln,  four  or  five  times, 
when  a  great  variety  of  colors  is  contained  in  the  painting. 

Gilding  upon  porcelain  is  performed,  by  applying  the 
gold,  after  its  solution  in  nitro-muriatic  acid,  ground  up 
with  oil  of  turpentine,  and  mixed  with  a  flux.  W^hen 
exposed  to  heat,  the  oxygen,  if  any  is  present,  escapes, 
and  a  coating  of  metallic  gold  remains  fixed  to  the  porce- 
lain. This  has,  at  first,  the  appearance  of  dead  gold  ; 
jut  is  subsequently  burnished,  with  an  instrument  of  pol- 
ished steel,  or  with  an  agate,  or  blood-stone. 

The  articles,  called  lustre-ware^  are  of  two  kinds.   The 


ETRUSCAN  VASES.  273 

first  of  these,  called  gold-lustre,  is  made  of  red  clay,  and 
is  brushed  over  with  a  thin  coating  of  gold,  obtained  frono 
its  solution  in  nitro-muriatic  acid,  the  acid  being  driven 
off  by  heat.  The  other  kind  is  called  silver-lustre,  and 
is  made  of  the  cream-colored  ware,  covered,  in  the  same 
manner,  with  a  film  of  platinum. 

Etruscan  Vases. — This  name  is  given  to  a  kind  of 
painted  antique  vases,  of  great  beauty,  lightness,  and 
delicacy,  which  are  dug  up  in  the  graves  of  lower  Italy. 
Many  of  them  are  supposed  to  be  of  Grecian,  and  not  of 
Etruscan,  origin.  Some  of  these  vases  are  entirely  black, 
and,  in  this  case,  there  is  no  separate  glazing  ;  but  the  m- 
terior  of  the  mass  has  the  same  appearance  with  the  out- 
side. Other  vases  are  furnished  with  a  simple  black 
coating,  but  unhke  the  modern  glazing.  It  appears,  from 
analysis,  that  this  black  color  is  produced  by  a  carbona- 
ceous substance,  perhaps  bitumen  ;  but  the  art  of  apply- 
ing it  is  unknown  to  the  moderns. 

The  celeh^ted  Portland  vase,  discovered  in  the  tomb 
of  xA.lexande^^everus,  and  for  w^hich  the  Dutchess  of 
Portland  paid  a  thousand  guineas,  is  said  to  be  made,  not 
of  porcelain,  but  of  glass.  The  body  of  the  urn  consists 
of  a  deep-blue  glass,  over  which  is  applied  a  coating  of 
white  semi-transparent  glass.  The  white  covering  ap- 
pears to  have  been  cut  away,  by  the  lapidary,  in  the  same 
way  as  the  subjects  of  antique  cameos  on  colored  grounds. 
Mr.  Wedgewood,  at  a  great  expense,  produced  imitations 
of  this  vase,  in  porcelain. 

Among  the  curiosities  of  this  art,  may  be  mentioned 
the  magic  porcelain  of  the  Chinese.  The  figures  upon 
the  surface  of  this  ware  are  executed  in  such  a  manner, 
that  they  are  said  to  be  invisible,  when  the  vessels  are 
empty,*  but  become  apparent,  when  the  vessels  are  filled 
with  water. 

WoivKs  ofReferbnce. — Parkks's  Chemical  Essays,  vol  ii. ; — 
Rees'  Cyclopedia,  and  Edinburgh  Encyclopedia,  articles  Pottery,  Por- 
celain, &c.  ; — Chaptal,  Chimie  Appliquee  aux  Arts,  torn.  iii.  ; — 
Gray's  Operative  Chemis-t,  8vo.  1828. — Lardner's  Cabinet  Cy- 
clopedia, 12mo.  vol.  xxvi. 

*  See  the  article  Porcelain^  in  the  Edinburgh  Encyclopedia,  ascribed 
to  M.  Brogniart. 


APPENDIX 


I.  —  Artesian  Wells. 

Under  this  name,  is  designated  a  cylindrical  perfora- 
tion, bored  vertically  down  through  one  or  more  of  the 
geological  strata  of  the  earth,  till  it  passes  into  a  porous 
gravel  bed,  containing  water  placed  under  such  incum- 
bent pressure,  as  to  make  it  mount  up  through  the  per- 
foration, either  to  the  surface,  or  to  a  height  convenient 
for  the  operation  of  a  pump.  In  the  first  case,  these 
wells  are  called  spouting,  or  overflowing.  This  property 
is  not  directly  proportional  to  the  depth,  as  might  at  first 
sight  be  supposed,  but  to  the  subjacent  pressure  upon  the 
water.  We  do  not  know  exactly  the  period,  at  which 
the  borer,  or  sound,  was  applied  to  the  investigation  of 
subterranean  fountains,  but  we  beheve  the  first  overflow- 
ing wells  were  made  in  the  ancient  French  province  of  Ar- 
tois,  whence  the  name  of  Artesian.  These  wells,  of  such 
importance  to  agriculture  and  manufactures,  and  which 
cost  nothing  to  keep  them  in  condition,  have  been  in  use, 
undoubtedly,  for  several  centuries,  in  the  northern  depart- 
ments of  France,  and  in  the  north  of  Italy  ;  but  it  is  not 
more  than  fifty  or  sixty  years,  since  they  became  known 
in  England  and  Germany.  There  are  now  many  such 
wells  in  London  and  its  neighborhood,  perforated  through 
the  immensely  thick  bed  of  the  London  clay,  and  even 
through  some  portions  of  the  subjacent  chalk.  The  bor- 
ing of  such  wells  has  given  much  insight  into  the  geologi- 
cal structure  of  many  districts. 

The  formation  of  Artesian  wells  depends  on  two  things, 
essentially  distinct  from  each  other  ;  1.  On  an  acquain- 
tance with  the  physical  constitution,  ornature,  of  the  min- 


276  APPENDIX. 

eral  structure  of  each  particular  country  ;  and,  2.  On  the 
skilful  direction  of  the  processes,  by  which  we  can  reach 
the  water-level,  and  of  those  by  which  we  can  promote  its 
ascent  in  the  tube.  We  shall  treat  of  the  best  method  of 
making  the  well,  and  then  offer  some  general  remarks  on 
the  other  subjects. 

The  operations  employed  for  penetrating  the  soil  are 
entirely  similar  to  those  daily  practised  by  the  miner,  in 
boring  to  find  metallic  veins  ;  but  the  well-excavator  must 
resort  to  peculiar  expedients  to  prevent  the  purer  water, 
which  comes  from  deep  strata,  mingling  with  the  cruder 
waters  of  the  alluvial  beds  near  the  surface  of  the  ground, 
as  also  to  prevent  the  small  perforation  getting  eventually 
filled  with  rubbish. 

The  cause  of  overflowing  wells  has  been  ascribed  to 
various  circumstances.  But,  as  it  is  now  generally  ad- 
mitted, that  the  numerous  springs. w^hich  issue  from  the 
ground  proceed  from  the  infiltration  of  the  waters,  pro- 
gressively condensed  in  rain,  dew,  snow,  &c.,  upon  the 
§urface  of  our  globe,  the  theory  of  these  interior  stream- 
lets becomes  by  no  means  intricate  ;  being  analogous  to 
that  of  syphons  and  water-jets,  as  expounded  in  the  trea- 
tises of  physics.  The  waters  are  diffused,  after  conden- 
sation, upon  the  surface  of  the  soil,  and  percolate  down- 
wards through  the  various  pores  and  fissures  of  the  geo- 
logical strata,  to  be  again  united  subterraneously  in  veins, 
rills,  streamlets,  or  expanded  films,  of  greater  or  less  mag- 
nitude or  regularity.  The  beds  traversed  by  numerous 
disjunctions  will  give  occasion  to  numerous  interior  cur- 
rents, in  all  directions,  which  cannot  be  recovered  and 
brought  to  the  day  ;  but  when  the  ground  is  composed 
of  strata  of  sand  or  gravel  very  permeable  to  water,  sep- 
arated by  other  strata  nearly  impervious  to  it,  reservoirs 
are  formed  to  our  hand,  from  w^hich  an  abundant  supply 
of  water  may  be  spontaneously  raised.  In  this  case,  as 
soon  as  the  upper  stratum  is  perforated,  the  waters  may 
rise,  in  consequence  of  the  hydrostatic  pressure  upq^  the 
lower  strata,  and  even  overflow  the  surface  in  a  constant 
stream,  provided  the  level  from  which  they  proceed  be 
proportionably  higher. 


ARTESIAN  WELLS.  277 

The  sheets  of  water  occur,  principally,  at  the  separa- 
tion of  two  contiguous  formations  ;  and,  if  the  succession 
of  the  geological  strata  be  considered,  this  distribution  of 
the  water  will  be  seen  to  be  its  necessary  consequence. 
In  fact,  the  lower  beds  are  frequently  composed  of  com- 
pact sandstone  or  hmestone,  and  the  upper  beds  of  clay. 
In  level  countries,  the  formations  being  almost  always  in 
horizontal  beds,  the  waters  which  feed  the  Artesian  wells 
must  come  from  districts  somewhat  remote,  where  the 
strata  are  more  elevated,  as  towards  the  secondary  and 
transition  rocks.  The  copious  streams,  condensed' upon 
the  sides  of  these  colder  lands,  may  be  therefore  regarded 
as  the  proper  reservoirs  of  our  wells. 

Th^  situation  of  the  intended  well  being  determined 
upon,  a  circular  hole  is  generally  dug  in  the  ground,  about 
six  or  eight  feet  deep,  and  five  or  six  feet  wide.  In  the 
centre  of  this  hole,  the  boring  is  carried  on  by  two  work- 
men below,  assisted  by  a  laborer  above. 

The  tools  used  are  variously  formed,  in  the  shape  of 
drills,  chisels,  picks,  &:c.,  screwed  upon  the  end  of  a 
handle  which  is  capable  of  being  lengthened,  as  the  work 
proceeds.  The  whole  is  suspended  from  an  elastic  hori- 
zontal pole,  which  is  firmly  fixed,  at  one  end,  while  the 
other  end  can  be  moved,  up  and  down,  by  a  workman, 
producing  a  vibrating,  or  picking,  motion.  At  the  same 
time,  other  workmen  turn  or  vary  the  position  of  the 
drill,  by  means  of  a  cross-bar,  so  that  it  acts  as  in  the 
common  mode  of  drilling  rocks.  The  dirt  and  broken 
stones  are  drawn  up,  by  an  instrument  shaped  somewhat 
like  an  auger,  which  is  inserted,  from  time  to  time,  when 
the  drill  is  withdrawn. 

It  is  obvious,  that  placing  and  displacing  the  lengths 
of  rod,  which  is  done  every  time  that  the  auger  is  required 
to  be  introduced  or  withdrawn,  nust,  of  itself,  be  ex- 
tremely troublesome,  independent  Df  the  labor  of  boring  ; 
but  yet  the  operation  proceeds,  when  no  unpropitious 
circymstance  attends  it,  with  a  facihty  almost  incredible. 
Sometimes,  however,  rocks  intercept  the  way,  which  re- 
quire great  labor  to  penetrate ;  but  this  is  always  efiectec 
by  pecking,  w^hich  slowly  pulverizes  the  stone.  The  most 
II.  24  XII. 


278  APPENDIX. 

unpleasant  circumstance  attendant  upon  this  business  is  the 
occasional  breaking  of  a  rod  into  the  hole,  which  some- 
times creates  a  delay  of  many  days,  and  an  incalculable 
labor  in  drawing  up  the  lower  portion. 

When  the  water  is  obtained,  in  such*  quantities  and  of 
such  quality  as  may  be  required,  the  hole  is  dressed  or 
finished,  by  passing  down  it  a  diamond  chisel,  funnel- 
mouthed,  with  a  triangular  bit  in  its  centre ;  this  makes 
the  sides  smooth,  previous  to  putting  in  the  pipe.  This 
chisel  is  attached  to  rods,  and  to  the  handle,  as  before 
described,  and  in  its  descent,  the  workmen  continually 
walk  round,  by  which  the  hole  is  made  smooth  and  cy- 
lindrical. In  the  progress  of  the  boring,  frequent  veins 
of  water  are  passed  through ;  but,  as  these  ai'e  small 
streams,  and  perhaps  impregnated  with  mineral  substances, 
the  operation  is  carried  on,  until  an  aperture  is  made  into 
a  main  spring,  which  will  flow  up  to  the  surface  of  the 
earth.  This  must,  of  course,  depend  upon  the  level  of 
its  source,  which,  if  in  a  neighboring  hill,  will  frequently 
cause  the  water  to  rise  up,  and  produce  a  continued  foun 
tain.  But,  if  the  altitude  of  the  distant  spring  happens  to 
be  below  the  level  of  the  surface  of  the  ground,  where  the 
boring  is  effected,  it  sometimes  happens,  that  a  well  of 
considerable  capacity  is  obliged  to  be  dug  down  to  that 
level,  in  order  to  form  a  reservoir,  into  which  the  water 
may  flow,  and  whence  it  must  be  raised  by  a  pump  ; 
while,  in  the  former  instance,  a  perpetual  fountain  may 
be  obtained.  Hence,  it  will  always  be  a  matter  of  doubt, 
in  level  countries,  whether  water  can  be  procured,  which 
would  flow  near  to,  6r  over,  the  surface  ;  if  this  cannot  be 
effected,  the  process  of  boring  will  be  of  litde  or  no  ad- 
vantage, except  as  an  experiment,  to  ascertain  the  fact. 

In  order  to  keep  the  strata  pure,  and  uncontaminated 
A^ith  mineral  springs,  the  hole  is  cased,  for  a  considerable 
lepth,  with  a  metallic  pipe,  about  a  quarter  of  an  incli 
mailer  than  the  bore.  This  is  generally  made  of  tin, 
viiough  sometimes  of  copper  or  lead,  in  convenient 
lengths  ;  and,  as  each  length  is  let  down,  it  is  held  by  a 
shoulder  resting  in  a  fork,  while  another  length  is  sol- 
dered to  it  ;  by  which  means  a  continuous  pipe  is  carried 


MINES.  279 

through  the  bore,  as  far  as  may  be  found  necessary,  to 
exclude  land-springs,  and  to  prevent  loose  earth  or  sand 
from  falling  in,  and  chdking  the  aperture. —  Ure^s  ^Diction- 
ary of  Arts, ^&ic. 

II. — Mines. 

Amidst  the  variety  of  bodies,  apparently  infinite,  which 
compose  the  crust  of  the  globe,  geologists  have  demon- 
strated the  prevalence  of  a  few  general  systems  of  rocks, 
to  which  they  have  given  the  names  of  formations,  or  de- 
posits. A  large  proportion  of  these  mineral  systems  con- 
sists of  parallel  planes,  Vvhose  length  and  breadth  greatly 
exceed  their  thickness  ;  on  w^hich  account,  they  are  called 
stratified  rocks  ;  others  occur  in  very  thick  blocks,  with- 
out any  parallel  stratification,  or  horizontal  seams,  of  con- 
siderable extent. 

The  stratiform  deposits  are  subdivided  into  two  great 
classes  ;  the  primary,  and  the  secondary.  The  former 
seem  to  have  been  called  into  existence,  before  the  crea- 
tion of  organic  matter,  because  they  contain  no  exuviae  of 
vegetable  or  animal  beings  ;  while  the  latter  are  more  or 
less  interspersed,  and  sometimes  replete,  with  organic  re- 
mains. The  primary  strata  are  characterized,  moreover, 
by  the  nearly  vertical,  or  highly  inclined,  position  of  their 
planes  ;  the  secondary  lie,  for  the  most  part,  in  a  nearly 
horizontal  position. 

Where  the  primitive  mountains  graduate  down  into  the 
plains,  rocks  of  an  intermediate  character  appear,  which, 
though  possessing  a  nearly  vertical  position,  contain  a  few 
vestiges  of  animal  beings,  especially  shells.  These  have 
been  called  transition,  to  indicate  their  being  the  passing 
links  between  the  first  and  second  systems  of  ancient  de- 
posits. They  are  distinguished  by  the  fractured  and  ce- 
mented texture  of  their  planes,  for  which  reason  they  are 
sometimes  called,  conglomerate. 

Between  these,  and  the  truly  secondary  rocks,  another 
very  valuable  series  is  interposed,  in  certain  districts  of 
the  globe  ;  namely,  the  coal-measures,  the  paramount  for- 
mation of  Great  Britain.  The  coal  strata  are  disposed 
in  a  basin  form,  and  alternate  with  parallel  beds  of  sand- 


280  APPENDIX. 

Stone,  slate-clay,  iron-stone,  and  occasionally  limestone. 
Some  geologists  have  called  the  coal-measures  the  medi- 
al formation.  • 

In  every  mineral  plane,  the  inchnation  and  direction  are 
to  he  noted  ;  the  former,  being  the  angle  ^vhich  it  forms 
with  the  horizon,  the  latter,  the  point  of  the  azimuth,  or 
horizon,  towards  which  it  dips,  as  west,  northeast,  south, 
&c.  The  direction  of  the  bed  is  that  of  a  horizontal  line 
drawn  in  its  plane  ;  and  which  is  also  denoted  by  the  point 
of  the  compass.  Since  the  lines  of  direction  and  inclina- 
tion are  at  right  angles  to  each  other,  the  first  may  always 
be  inferred  from  the  second  ;  for  when  a  stratum  is  said 
to  dip  to  the  east  or  west,  this  implies,  that  its  direction 
is  north  and  south. 

The  smaller  sinuosities  of  the  bed  are  not  taken  into 
account,  just  as  the  windings  of  a  river  are  neglected,  in 
stating  the  line  of  its  course. 

Masses  are  mineral  deposits,  not  extensively  spread  m 
parallel  planes,  but  irregular  heaps,  rounded  or  oval,  en- 
veloped, in  whole  or  in  a  great  measure,  by  rocks  of  a 
different  kind.  Lenticular  masses  being  frequently  placed 
between  two  horizontal,  or  inclined,  strata,  have  been 
sometimes  supposed  to  be  stratiform  themselves,  and 
have  been  accordingly  denominated  by  the  Germans, 
liegende  stocke^  ^^**^^  heaps,  or  blocks. 

The  orbicular  masses  often  occur  in  the  interior  of  un- 
stratified  mountains,  or  in  the  bosom  of  one  bed. 

.A'es^s,  concretions,  nodules,  are  small  masses  found* in 
the  middle  of  strata  ;  the  first  being  commonly  in  a  fria- 
ble state  ;  the  second  often  kidney-shaped,  or  tuberous  ; 
the  third  nearly  round,  and  encrusted,  like  the  kernel  of 
an  almond. 

Lodes,  or  large  veins,  are  flattened  masses,  with  their 
opposite  surfaces  not  parallel,  which  consequently  termi- 
nate like  a  wedge,  at  a  greater  or  less  distance,  and  do 
not  run  parallel  with  the  'rocky  strata  in  which  they  lie, 
but  cross  them,  in  a  direction  not  far  from  the  perpendic- 
ular ;  often  traversing  several  different  mineral  planes. 
The  lodes  are  sometimes  deranged  in  their  course,  so  as 
to  pursue,  for  a  little  way,  the  spEce  between  two  con- 


MINES.  281 

t^guous  strata  ;  at  other  times  they  divide,  into  several 
branches.  The  matter  which  fills  the  lodes  is,  for  the 
most  part,  entirely  different  from  the  rocks  they  pass 
through  ;  or,  at  least,  it  possesses  peculiar  features. 

This  mode  of  existence,  exhibited  by  several  mineral 
substances,  but  which  has  been  long  known  with  regard  to 
metallic  ores,  suggests  the  idea  of  clefts,  or  rents,  having 
been  made  in  the  stratum,  posterior  to  its  consolidation 
and  of  the  vacuities  having  been  filled  with  foreign  matter, 
either  immediately,  or  after  a  certain  interval.  There 
can  be  no  doubt,  as  to  the  justness  of  the  first  part  of  the 
proposition,  for  there  may  be  observed,  round  many  lodes, 
undeniable  proofs  of  the  movement  or  dislocation  of  the 
rock  ;  for  example,  upon  each  side  of  the  rent,  the  same 
strata  are  no  longer  situated  in  the  same  plane  as  before, 
but  make  greater  or  smaller  angles  with  it ;  or  the  stratum 
upon  one  side  of  the  lode  is  raised  considerably  above,  or 
depressed  considerably  below,  its  counterpart,  upon  the 
other  side.  Whh  regard  to  the  manner  in  which  the  rent 
has  been  filled,  different  opinions  may  be  entertained.  In 
the  lodes  which  are  widest,  near  the  surface  of  the  ground, 
and  graduate  into  a  thin  wedge,  below,  the  foreign  matter 
would  seem  to  have  been  introduced,  as  into  a  funnel,  at 
the  top,  and  to  have  carried  along  with  it,  in  its  fluid  state, 
portions  of  rounded  gravel  and  organic  remains.  In  oth- 
er cases,  other  conceptions  seem  to  be  more  probable  ; 
since  many  lodes  are  largest,  at  their  under  part,  and  be- 
come progressively  narrower,  as  they  approach  the  sur- 
face ;  from  which  circumstance  it  has  been  inferred,  that 
the  rent  has  been  caused  by  an  expansive  force,  acting 
from  within  the  earth,  and  that  the  foreign  matter,  having 
been  injected  in  a  fluid  state,  has  afterwards  slowly  crys- 
tallized. This  hypothesis  accounts,  much  better  than  the 
other,  for  most  of  the  phenomena  observable  in  mineral 
veins,  for  the  alterations  of  the  rock  at  their  sides,  for  the 
crystaUization  of  the  different  substances  interspersed  in 
them,  for  the  cavities  bestudded  with  little  crystals,  and 
for  many  minute  peculiarities.  Thus,  the  large  crystals 
of  certain  substances,  which  line  the  walls  of  hollow  veins, 
have  sometimes  their  under  surfaces  besprinkled  with 
24* 


282  APPENDIX. 

small  crystals  of  sulphurets,  arseniurets,  &c.,  while  their 
upper  surfaces  are  quite  smooth  ;  suggesting  the  idea  ol  a 
slow  sublimation  of  these  volatile  matters  from  below,  by 
the  residual  heat,  and  their  condensation  upon  the  under 
faces  of  the  crystalline  bodies,  already  cooled.  This  phe- 
nomenon affords  a  strong  indication  of  the  igneous  origin 
of  metalliferous  veins. 

In  the  lodes,  the  principal  matters  which  fill  them  are 
to  be  distinguished  from  the  accessory  substances  ;  the 
latter  being  distributed,  irregularly,  amidst  the  mass  of 
the  first,  in  crystals,  nodules,  veins,  seams,  &c.  The 
non-metalliferous  exterior  portion,  which  is  often  the 
largest,  is  called  gangue,  from  the  German  gang^  vein. 
The  position  of  a  vein  is  denoted,  like  that  of  the  strata, 
by  the  angle  of  inclination,  and  the  point  of  the  horizon 
towards  which  they  dip,  whence  the  direction  is  deduced. 

Veins  are  merely  small  lodes,  which  sometimes  tra- 
verse the  great  ones,  ramifying,  in  various  directions,  and 
in  different  degrees  of  tenuity. 

A  metalliferous  substance  is  said  to  be  disseminated , 
when  it  is  dispersed  in  crystals,  spangles,  scales,  globules, 
&c.,  through  a  large  mineral  mass. 

Certain  ores,  which  contain  the  metals  most  indispensa- 
ble to  human  necessities,  have  been  treasured  up  by  the 
Creator  in  very  bountiful  deposits  ;  constituting  either 
great  masses  in  rocks  of  different  kinds,  or  distributed  in 
lodes,  veins,  nests,  concretions,  or  beds,  with  stony  and 
earthy  admixtures  ;  the  w^hole  of  which  become  the  ob- 
jects of  mineral  exploration.  These  precious  stones  occur 
in  different  stages  of  the  geological  formations,  but  their 
main  portion,  after  having  existed,  abundantly,  in  the  sev- 
eral orders  of  the  primary  strata,  suddenly  cease  to  be 
found,  towards  the  middle  of  the  secondary.  Iron  ores 
are  the  only  ones  which  continue  among  the  more  mod- 
ern deposits,  even  so  high  as  the  beds  immediately  beneath 
the  chalk,  when  they  also  disappear,  or  exist  merely  as 
coloring  miitters  of  the  tertiary  earthy  beds. 

The  strata  of  gneiss  and  mica-slate  constitute,  in  Eu- 
rope, the  grand  metallic  domain.  There  is  hardly  any 
kind  of  ore,  which  does  not  occur  there  in  sufficient  abun- 


MINES.  283 

dance,  to  become  the  object  of  mining  operations,  and 
many  are  found  nowhere  else.  The  transition  rocks, 
and  the  lower  part  of  the  secondary  ones,  are  not  so  rich, 
neither  do  they  contain  the  same  variety  of  oyes.  But 
this  order  of  things,  which  is  presented  by  Great  Britain, 
Germany,  France,  Sweden,  and  Norway,  is  far  from 
forming  a  general  law  ;  since  in  Equinoctial  America,  the 
gneiss  is  but  little  metalliferous  ;  while  the  superior  b.Tata, 
such  as  the  clay-schists,  the  sienitic  porphyries,' the  lime- 
stones, which  complete  the  transition  series,  as  also  sev- 
eral secondary  deposits,  include  the  greater  portion  of. 
the  immense  mineral  wealth  of  that  region  of  the  globe. 

All  the  substances,  of  which  the  ordinary  metals  form 
the  basis,  are  not  equally  abundant  in  Nature  ;  a  great 
proportion  of  the  numerous  mineral  s])ecies,  which  figure 
in  our  classifications,  are  mere  varieties,  scattered  up  and 
down  in  the  cavities  of  the  great  masses,  or  lodes.  The 
workable  ores  are  few  in  number,  being  mostly  sulphurets, 
some  oxides,  and  carbonates.  These  occasionally  form, 
of  themselves,  very  large  masses  ;  but,  more  frequently, 
they  are  blended  with  lumps  of  quartz,  feldspar,  and  car- 
bonate of  lime,  which  form  the  main  body  of  the  deposit  ; 
as  happens,  always,  in  proper  lodes.  The  ores,  in  that 
case,  are  arranged  in  small  layers,  parallel  to  the  strata  oi 
the  formation,  or  in  small  veins,  which  traverse  the  rock 
in  all  directions,  or  in  nests,  or  concretions,  stationed  ir- 
regularly, or  finally  disseminated,  in  hardly  visible  parti- 
cles. These  deposits  sometimes  contain,  apparently, 
only  one  species  of  ore,  sometimes  several,  which  must 
be  mined  together,  as  they  seem  to  be  of  contemporane- 
ous formation  ;  whilst,  in  other  cases,  they  are  separable, 
havmg  been  probably  formed  at  different  epochs. 

Lodes,  or  mineral  veins,  are  usually  distinguished,  by 
English  miners,  into  at  least  four  species.  1.  The  rake- 
vein  ;  2.  The  pipe-vein ;  3.  The  flat,  or  dilated,  vein  ; 
and  4.  The  interlaced  mass,  (stock-tDerke^)  indicating  the 
union  of  a  multitude  of  small  veins,  mixed,  in  every  possi- 
ble direction,  with  each  other  and  with  the  rock. 

1.  The  rake  vein  is  a  perpendicular  mineral  fissure  ; 
and  is  the  form  best  known  among  practical  miners.     It 


284  APPENDIX. 

commonly  runs  in  a  straight  line,  beginning  at  the  super- 
ficies of  the  strata,  and  cutting  them  downwards,  generally 
further  than  can  be  reached.  This  vein  sometimes  stands 
quite  perpendicular  ;  but  it  more  usually  inclines,  or  hangs 
over,  at  a  greater  or  smaller  angle,  or  slope,  which  is 
called,  by  the  miners,  the  hade,  or  hading,  of  the  vein. 
The  line  of  direction  in  which  the  fissure  runs  is  called, 
the  bearing  of  the  vein. 

2.  Tlie  pipe  vein  resembles,  in  many  respects,  a  huge, 
irregular  cavern,  pushing  forward  into  the  body  of  the 
earth,  in  a  sloping  direction,  under  various  inclinations, 
from  an  angle  of  a  (ew  degrees  to  the  horizon,  to  a  dip  of 
forty-five  degrees,  or  more.  The  pipe  does  not,  in  general, 
cut  the  strata  across,  like  the  rake-vein,  but  insinuates 
itself  between  them  ;  so  that,  if  the  plane  of  the  strata  be 
nearly  horizontal,  the  bearing  of  the  pipe-vein  will  be  con- 
formable ;  but  if  the  strata  stand  up  at  a  high  angle,  the 
pipe  shoots  down,  nearly  headlong,  like  a  shaft.  Some 
pipes  are  very  wide  and  high,  others  are  very  low  and 
narrow,  sometimes  not  larger  than  a  common  mine,  or 
drift. 

3.  The^a^,  or  dilated,  vein  is  a  space  or  opening,  be- 
tween two  strata  or  beds  of  stone,  the  one  of  which  lies 
above,  and  the  other  below,  this  vein,  like  a  stratum  of 
coal  between  its  roof  and  pavement  ;  so  that  the  vein  and 
the  strata  are  placed  in  the  same  plane  of  inclination. 
These  veins  are  subject,  like  coal,  to  be  interrupted, 
broken,  and  thrown  up  or  down,  by  slips,  dykes,  or  other 
interruptions  of  the  regular  strata.  In  the  case  of  a  me- 
tallic vein,  a  slip  often  increases  the  chance  of  finding 
more  treasure.  Such  veins  do  pot  preserve  the  parallel- 
ism of  their  beds,  characteristic  «^f  coal-seams  ;  but  vary, 
excessively,  in  thickness,  within  a  moderate  space.  Flat 
veins  occur,  frequently,  in  limestone,  either  in  a  horizontal 
or  declining  direction.  The  flat,  or  strata,  veins  open  and 
close,  as  the  rake-veins  also  do. 

To  these  may  be  added,  the  accumulated  vein,  or  ij- 
regularmass,  {hutzenwerke,)  a  great  deposit,  placed,  with- 
out any  order,  in  the  bosom  of  the  rocks,  apparently 
filling  up  cavernous  spaces. 


MINES.  28b 

The  interlaced  masses  are  more  frequent  in  primitive 
formations,  than  in  the  others,  and  tin  is  the  ore  which 
most  commonly  affects  this  locality. 

These  gangues,  such  as  quartz,  calcareous  spar,  fluor 
spar,  heavy  spar,  &c.,  and  a  great  number  of  other  sub- 
stances, although  of  little  or  no  value  in  themselves,  be- 
come of  great  consequence  to  the  miner,  either  by  point- 
ing out,  by  their  presence,  that  of  certain  useful *hiinerals, 
or  by  characterising,  in  their  several  associations,  difier- 
ent  deposits  of  ores,  of  which  it  may  be  possible  to  follow 
the  traces,  and  to  discriminate  the  relations,  often  of  a 
comphcated  kind,  provided  we  observe  assiduously  the 
accompanying  gangues. 

Mineral  veins  are  subject  to  derangements,  in  their 
course,  which  are  called  shifts,  or  faults.  Thus,  when  a 
transverse  vein  throws  out,  or  intercepfs  a  longitudinal  one, 
we  must  commonly  look  for  the  rejected  vein  on  the  side  of 
the  obtuse  angle,  which  the  direction  of  the  latter  makes 
with  that  of  the  former.  When  a  bed  of  ore  is  deranged 
by  a  fault,  we  must  observe,  whether  the  shp  of  the  strata 
be  upwards  or  downwards  ;  for,  in  either  circumstance,  it 
is  only  by  pursuing  the  direction  of  the  fault,  that  we  can 
recover  the  ore  ;  in  the  former  case,  by  mounting,  in  the 
latter,  by  descending,  beyond  the  dislocation. 

When  two  veins  intersect  each  other,  the  direction  of 
the  offcast  is  a  subject  of  interest,  both  to  the  miner  and 
the  geologist.  In  Saxony,  it  is  considered  as  a  general 
fact,  that  the  portion  thrown  out  is  always  upon  the  side 
of  the  obtuse  angle,  a  circumstance  which  holds  also  in 
Cornwall  ;  and  the  more  obtuse  the  angle,  the  out-throw 
is  the  more  considerable.  A  vein  may  be  thrown  out,  on 
meeting  another  vein,  in  a  line  which  approaches  either 
towards  its  inclination,  or  its  direction.  The  Cornish 
miners  use  two  different  terms,  to  denote  these  two  modes 
of  rejection  ;  for  the  first  case,  they  say  the  vein  is 
heaved  ;  for  the  second,  it  is  started. 

GENERAL  OBSERVATIONS  ON  THE  LOCALITIES  OF  ORES 
AND   ON  THE   INDICATIONS    OF   METALLIC  MINES, 

1.    Tin  exists,  principally,  in  primitive  rocks,  appearing 


286  APPENDIX. 

either  in  interlaced  masses,  in  beds,  or  as  a  constituent 
part  of  the  rock  itself,  and,  more  rarely,  in  distinct  veins. 
Tin  ore  is  found  indeed,  sometimes,  in  alluvial  land,  filling 
up  low  situations  between  lofty  mountains. 

2.  Gold  occurs  either  in  beds,  or  in  veins,  frequently 
in  primitive  rocks ;  though,  in  other  formations,  and  par- 
ticularly in  alluvial  earth,  it  is  also  found.  When  this 
metal  exfsts  in  the  bosom  of  primitive  rocks,  it  is  partic- 
ularly in  schists ;  it  is  not  found  in  serpentine,  but  it  is 
met  with  in  gray-wacke,  in  Transylvania.  The  gold  of 
alluvial  districts,  called  gold  of  washing,  or  transport,  oc- 
curs, as  well  as  alluvial  tin,  among  the  debris  of  the  more 
ancient  rocks. 

'  3.  Silver  is  found,  particularly  in  veins  and  beds,  in 
primitive  and  transition  formations  ;  though  some  veins  of 
this  metal  occur  in  'secondary  strata.  The  rocks,  richest 
in  it,  are,  gneiss,  mica-slate,  clay-slate,  gray-wacke,  and 
old  alpine  limestone.  Localities  of  silver  ore  itself  are  not 
numerous,  at  least  in  Europe,  among  secondary  forma- 
tions ;  but  it  occurs  in  combination  with  the  ores  of  cop' 
per,  or  of  lead. 

4.  Copper  exists  in  the  three  mineral  epochas  :  1.  in 
primitive  rocks,  principally  in  the  state  of  pyritous  copper, 
in  beds,  in  masses,  or  in  veins ;  2.  in  transition  districts, 
sometimes  in  masses,  sometimes  in  veins  of  copper  py- 
rites ;  3.  in  secondary  strata,  especially  in  beds  of  cupre- 
ous schist. 

5.  Lead  occurs,  also,  in  each  of  the  three  mineral  epo- 
chas ;  abounding,  particularly,  in  primitive  and  transition 
grounds,  where  it  usually  constitutes  veins,  and  occasion- 
ally beds,  of  sulphuretted  lead,  (galena.)  The  same  ore 
is  found  in  strata,  or  in  veins,  among  secondary  rocks,  as- 
sociated, now  and  then,  with  ochreous  iron-oxide  and  cal- 
amine, (carbonate  of  zinc,)  and  it  is  sometimes  dissemi- 
nated, in  grains,  through  more  recent  strata. 

6.  Iron  is  met  with,  in  four  different  mineral  eras,  but 
in  different  ores.  Among  primitive  rocks,  magnetic  iron 
ore  and  specular  iron  ore  occur  chiefly  in  beds,  some- 
times of  enormous  size  ;  the  ores  of  red,  or  brown,  oxide 
of  iron  (haematite)  are  found  generally  in  veins,  or,  occa- 


MINES.  287 

sionally,  in  masses  with  sparry  iron,  both  in  primitive  and 
transition  rocks  ;  as  also,  sometimes,  in  secondary  strata  ; 
but,  more  frequently,  in  the  coal-measure  strata,  as  beds 
of  clay-ironstone,  of  globular  iron-oxide,  and  carbonate 
of  iron.  In  alluvial  districts,  we  find  ores  of  clay-iron- 
stone, granular  iron-ore,  bog-ore,  swamp-ore,  and  mead- 
ow-ore. The  iron  ores,  which  belong  to  the  primitive 
period,  have  almost  always  the  metallic  aspect,  wiih  a 
richness  amounting  even  to  eighty  per  cent,  of  iron,  while 
the  ores  in  the  posterior  formations  become,  in  general, 
more  and  mo're  earthy,  down  to  those  in  alluvial  soils, 
some  of  which  present  the  appearance  of  a  common  stone, 
and  afford  not  more  than  twenty  per  cent,  of  metal,  though 
its  quahty  is  often  excellent. 

7.  Mercury  occurs  principally  among  secondary  stra- 
ta, in  disseminated  masses,  along  with  combustible  sub- 
stances ;  though  the  metal  is  met  with,  occasionally,  in 
primitive  countries. 

8.*  Cobalt  belongs  to  the  three  mineral  epochas  ;  i.6 
most  abundant  deposits  are  veins  in  primitive  rocks. 
Small  veins,  containing  this  metal,  are  found,  however,  in 
secondary  strata. 

9.  Antimony  occurs  in  veins,  or  beds,  among  primitive 
and  transition  rocks. 

10,  11.  Bismuth  and  nickel  do  not  appear  to  consti- 
tute the  predominating  substance  of  any  mineral  deposits  ; 
but  they  often  accompany  cobalt. 

12.  Zinc  occurs  in  the  three  several  formations  ;  name- 
ly, as  sulphuret  or  blende,  particularly  in  primitive  and  tran- 
sition rocks  ;  as  calamine,  in  secondary  strata,  usually  along 
with  oxide  of  iron,  and  sometimes  with  sulphuret  of  lead. 

An  acquaintance  with  the  general  results,  collected  and 
classified  by  geology,  must  be  our  first  guide  in  the  inves- 
tigation  of  mines.  This  enables  the  observer  to  judge, 
whether  any  particular  district  should,  from  the  nature 
and  arrangement  of  its  rocks,  be  susceptible  of  including 
within  its  bosom,  beds  of  workable  ores.  It  indicates, 
also,  to  a  certain  degree,  what  substances  may  probably 
be  met  with  in  a  given  series  of  rocks,  and  what  locality 
these  substances  will  preferably  affect      For  want  of  a 


288  APPENDIX. 

knowledge  of  these  facts,  many  persons  have  gone  blindly 
into  researches,  equally  absurd  and  ruinous. 

Formerly,  indications  of  mines  were  taken  from  very 
unimportant  circumstances  ;  from  thermal  waters,  the  heat 
of  which  was  gratuitously  referred  to  the  decomposition 
of  pyrites  ;  from  mineral  waters,  whose  course  is,  howev- 
er, often  from  a  far  distant  source  ;  from  vapours  incum- 
bent over  particular  mountain  groups  ;  from  the  snows 
melting  faster  in  one  mineral  district  than  another  ;  from 
the  difterent  species  of  forest  trees,  and  from  the  greater 
or  less  vigor  of  vegetation,  &c.  In  general,  all  such  in- 
dications are  equally  fallacious  with  the  divining  rod,  and 
the  compass  made  of  a  lump  of  pyrites,  suspended  by  a 
thread. 

Geognostic  observation  has  substituted  more  rational 
characters  of  metallic  deposits,  some  of  which  may  be 
called  negative^  and  others  positive. 

The  negative  indications  are  derived  from  that  peculiar 
geological  constitution,  which,  from  experience,  or  getieral 
principles,  excludes  certain  metallic  matters  ;  for  example, 
granite,  and,  in  general,  every  primitive  formation,  forbids 
the  hope  of  finding  within  them  combustible  fossils,  (pit- 
coal,)  unless  it  be  beds  of  anthracite  ;  there  also  it  would  be 
vain  to  seek  for  sal  gem.  It  is  very  seldom  that  granite 
rocks  include  silver  ;  or  limestones,  ores  of  tin.  Volcanic 
territories  never  afford  any  metallic  ores  worth  the  work- 
ing ;  nor  do  extensive  veins  usually  run  into  secondary  ana 
alluvial  formations.  The  richer  ores  of  iron  do  not  occur 
in  secondary  strata  ;  and  the  ores  of  this  metal,  peculiar 
to  these  localities,  do  not  exist  among  primary  rocks. 

Among  positive  indications,  some  are  proximate,  and 
others  remote.  Tne  proximate  are,  an  efflorescence,  so 
to  speak,  of  the  subjacent  metallic  masses  ;  magnetic  at- 
traction, for  iron  ores  ;  bituminous  stone,  or  inflammable 
gas,  for  pit-coal  ;  the  frequent  occurrence  of  fragments 
of  particular  ores,  &c.  The  remote  indications  consist 
in  the  geological  epocha  and  nature  of  the  rocks.  From 
the  examples  previously  adduced,  marks  of  this  kind  ac- 
quire new  importance,  when,  in  a  district  susceptible  of 
including  deposits  of  workable  ores,  the  gangues,  or  vein- 


•  MINES.  289 

stones,  are  met  with,  which  usually  accompany  any  partic 
ular  metal.  The  general  aspect  of  mountains,  whose 
flanks  present  gentle  and  continuous  slopes,  the  frequency 
of  sterile  veins,  the  presence  of  metalliferous  sands,  the 
neighborhood  of  some  known  locality  of  an  ore,  for  in- 
stance, that  of  iron-stone,  in  reference  to  coal  ;  lastly, 
the  existence  of  salt  springs  and  mineral  waters  may  fur- 
nish some  indications. 

In  speaking  of  remote  indications,  we  may  remark,  that, 
in  several  places,  and  particularly  near  Clausthal,  in  the 
Hartz,  a  certain  ore  of  red  oxide  of  iron  occurs  above  the 
most  abundant  deposits  of  the  ores  of  lead  and  silver  ; 
whence  it  has  been  named  by  the  Germans,  the  iron-hat. 
It  appears  that  the  iron  ore,  rich  in  silver,  which  is  worked 
in  America,  under  the  name  of  pacos,  has  some  analogy 
with  this  substance  ;  but 'iron  ore  is,  in  general,  so  plen- 
tifully diffused  on  the  surface  of  the  soil,  that  its  presence 
can  be  regarded  as  only  a  remote  indication,  relative  to 
other  mineral  substances,  except  in  the  case  of  clay-iron- 
stone with  coal. 

Of  the  instruments  and  processes  of  subterranean  op- 
erations.— It  is  by  the  aid  of  geometry,  in  the  first  place, 
that  the  miner  studies  the  situation  of  the  mineral  depos- 
its, on  the  surface,  and  in  the  interior,  of  the  ground  ;  de- 
termines the  several  relations  of  the  veins  and  the  rocks  ; 
and  becomes  capable  of  directing  the  perforations  towards 
a  suitable  end. 

The  instruments  are,  1.  The  magnetic  compass,  which 
is  employed  to  measure  the  direction  of  a  metallic  ore, 
wherever  the  neighborhood  of  iron  does  not  interfere  with 
:ts  functions.  2.  The  graduated  semicircle,  which  serves 
to  measure  the  inchnation,  which  is  also  called  the  cli- 
nometer. 3.  The  chain,  or  cord,  for  measuring  the  dis- 
tance of  one  point  from  another.  4.  When  the  neighbor- 
hood of  iron  renders  the  use  of  the  magnet  uncertain,  a 
plate,  or  plane  table,  is  employed. 

The.  dials  of  the  compasses,  generally  used  in  the  most 
celebrated  mines,  are  graduated  into  hours  ;  most  com- 
monly into  twice  twelve  hours.     Thus  the  whole  limb  is 
divided  into  twenty-four  spaces,  each  of  which  contains 
II.  25  XII 


290  APPENDIX. 

fifteen  degrees,  equal  to  one  hour.  Each  hour  is  subdi- 
vided into  eight  parts. 

Means  of  penetrating  into  the  interior  of  the  earth. — > 
In  order  to  penetrate  into  the  interior  of  the  earth,  and  to 
extract  from  it  the  objects  of  his  toils,  the  miner  has  at 
his  disposal  several  means,  which  may  be  divided  into  three 
classes  ;  1.  manual  tools,  2.  gunpowder ,  and  3.  fire. 
The  tools  used  by  the  miners  of  Cornwall  and  Devonshire 
are  the  following  : 

The  pick.  It  is  a  light  tool,  and  somewhat  varied  in 
shape,  according  to  circumstances  One  side,  used  as  a 
hammer,  is  called  the  poll,  and  is  employed  to  drive  in  the 
gads,  or  to  loosen  and  detach  prominences.  The  point 
is  of  steel,  carefully  tempered,  and  drawn  under  the  ham- 
mer to  the  proper  form.      The  French  call  it  pointerolle. 

The  gad.  It  is  a  wedge  of  steel,  driven  into  crev- 
ices of  rocks,  or  into  small  openings  made  with  the  point 
of  the  pick. 

The  minerh  shovel.  It  has  a  pointed  form,  to  ena- 
ble it  to  penetrate  among  the  coarse  and  hard  fragments 
of  the  mine  rubbish.  Its  handle  being  somewhat  bent,  a 
man's  power  may  be  conveniently  applied,  without  bend- 
ing his  body.  The  blasting,  or  shooting,  tools  are,  a 
sledge  or  mallet,  borer,  claying-bar,  needle  or  nail,  scra- 
per, tamping-bar.  Besides  these  tools,  the  miner  requires 
a  powder-horn,  rushes  to  be  filled  with  gunpowder,  tin  car- 
tridges, for  occasional  use  in  wet  ground,  and  paper  rubbed 
over  with  gunpowder,  or  grease,  for  the  smifts,  or  fuses. 

The  borer  is  an  iron  bar,  tipped  with  steel,  formed 
like  a  thick  chisel,  and  is  used  by  one  man  holding  it 
straight  in  the  hole,  with  constant  rotation  on  its  axis,  while 
another  strikes  the  head  of  it,  with  the  iron  sledge,  or 
mallet.  The  hole  is  cleared  out,  from  time  to  time,  by 
the  scraper,  which  is  a  flat  iron  rod,  turned  up  at  one  end. 
If  the  ground  be  very  wet,  and  the  hole  gets  full  of  mud, 
it  is  cleaned  out  by  a  stick,  bent  at  the  end  into  a  fibrous 
brush,  called  a  swab-stick. 

The  hole  must  be  rendered  as  dry  as  possible,  which  is 
effected  very  simply,  by  filling  it  partly  with  tenacious 
flay,  and  then  driving  into  it  a  tapering  iron  rod,  which 


MINES.  291 

nearly  fills  its  calibre,  called  the  claying-har.  This  be- 
ing forced  in  with  great  violence  condenses  the  clay  into 
all  the  crevices  of  the  rock,  and  secures  the  dryness  of 
the  hole.  Should  this  plan  fail,  recourse  is  had  to  tin 
cartridges,  furnished  with  a  stem,  or  tube,  through  which 
the  powder  may  be  inflamed.  When  the  holt  is  dry,  and 
the  charge  of  powder  introduced,  the  nail^  a  small  taper 
rod  of  copper,  is  inserted,  so  as  to  reach  the  bottom  of  the 
hole,  which  is  now  ready  for  tamping.  By  this  difficult 
and  dangerous  process,  the  gunpowder  is  confined,  and 
the  disruptive  effect  produced.  Different  substances  are 
employed  for  tamping ^  or  cramming  the  hole,  the  most 
usual  one  being  any  soft  species  of  rock,  free  from  sili- 
cious,  or  flinty,  particles.  Small  quantities  of  it  only  are 
introduced  at  a  time,  and  rammed  very  hard,  by  the  tamp- 
ing-bar^  which  is  held  steadily  by  one  man,  and  struck 
with  a  sledge  by  another.  The  hole  being  thus  filled,  the 
nail  is  withdrawn,  by  putting  a  bar  through  its  eye,  and 
striking  it  upwards.  Thus,  a  small  perforation,  or  vent, 
is  left  for  the  rush  which  communicates  the  fire. 

Besides  the  improved  tamping-bar,  faced  with  hard  cop- 
per, other  contrivances  have  been  resorted  to,  for  dimin- 
ishing the  risk  of  those  dreadful  accidents  that  frequently 
occur  in  this  operation.  Dry  sand  is  sometimes  used  as 
a  tamping  material  ;  but  there  are  many  rocks,  for  the 
blasting  of  which  it  is  ineffective.  Tough  clay  will  answer 
better,  in  several  situations.  For  conveying  the  fire,  the 
large  and  long  green  rushes,  which  grow  in  marshy  ground, 
are  selected.  A  slit  is  made  in  one  side  of  the  rush, 
along  which  the  sharp  end  of  a  bit  of  stick  is  drawn,  so  as 
to  extract  the  pith,  when  the  skin  of  the  rush  closes  again, 
by  its  own  elasticity.  This  tube  is  filled  up  with  gunpow- 
der, dropped  into  the  vent-hole,  and  made  steady  with  a 
bit  of  clay.  A  paper  smift.,  adjusted  to  burn  a  proper 
time,  is  then  fixed  to  the  top  of  the  rush  tube,  and  kindled, 
when  the  men  of  the  mine  retire  to  a  safe  distance. 

Gunpowder  is  the  most  valuable  agent  of  excavation  , 
possessing  a  power  which  has  no  limit,  and  which  can  act 
every  where,  even  under  water.  Its  introduction,  in  1615, 
caused  a  great  revolution  in  the  mining  art. 


292  APPENDIX. 

It  is  employed  in  mines,  in  different  manners,  and  in 
different  quantities,  according  to  circumstances.  In  all 
cases,  however,  the  process  resolves  itself  into  boring  a 
hole,  and  enclosing  a  cartridge  in  it,  which  is  afterwards 
made  to  explode.  The  hole  is  always  cylindrical,  and  is 
usually  madf  by  means  of  the  borer,  a  stem  of  iron  ter- 
minated by  a  blunt-edged  chisel.  It  sometimes  ends  in  a 
cross,  formed  by  two  chisels  set  transversely.  The  work- 
man holds  the  stem  in  his  left  hand,  and  strikes  it  w^ith  an 
iron  mallet,  held  in  his  right.  He  is  careful  to  turn  the 
punch  a  very  little  round,  at  every  stroke.  Several  punches 
are  employed,  in  succession,  to  bore  one  hole ;  the  first 
shorter,  the  latter  ones  longer,  and  somewhat  thinner. 
The  rubbish  is  whhdrawn,  as  it  accumulates  at  the  bottom 
of  the  hole,  by  means  of  a  picker,  which  is  a  small  spoon, 
or  disc  of  iron,  fixed  at  the  end  of  a  slender  iron  rod. 
When  holes  of  a  large  size  are  to  be  made,  several  men 
must  be  employed ;  one,  to  hold  the  punch,  and  one  or 
more,  to  wield  the  iron  mallet.  The  perforations  are  sel- 
dom less  than  an  inch  in  diameter,  and  eighteen  inches 
deep ;  but  they  are  sometimes  tw^o  inches  wide,  with  a 
depth  of  fifty  inches. 

The  gunpowder,  when  used,  is  most  commonly  put  up 
in  paper  cartridges.  Into  the  side  of  the  cartridge,  a  small 
cylindrical  spindle,  or  piercer^  is  pushed.  In  this  state, 
the  cartridge  is  forced  down  to  the  bottom  of  the  hole, 
which  is  then  stuffed,  by- means  of  the  tamping-bar,  with 
bits  of  dry  clay,  or  friable  stones  coarsely  pounded.  The 
peircer  is  now  withdrawn,  which  leaves  in  its  place  a 
channel,  through  which  fire  may  be  conveyed  to  the  charge. 
This  is  executed,  either  by  pouring  gunpowder  into  that 
passage,  or  by  inserting  into  it,  reeds,  straw-stems,  quills, 
or  tubes  of  paper,  filled  with  gunpowder.  This  is  explod- 
ed by  a  long  match,  which  the  workmen  kindle,  and  then 
retire  to  a  place  of  safety. 

As  the  piercer  must  not  only  be  slender,  but  stiff,  so 
as  to  be  easily  withdrawn  when  the  hole  is  tamped,  iron 
spindles  are  usually  employed,  though  they  occasionally 
give  rise  to  sparks,  and,  consequently,  to  dangerous  acci- 
dents, by  their  friction  against  the  sides  of  the  hole.    Brass 


MINES  5?^3 

piercers  have  been  sometimes  tried,  but  they  twist  and 
break  too  readily 

Each  hole  bored  in  a  mine  should  be  so  placed,  in  ref- 
erence to  the  schistose-structure  of  the  rock,  and  to  its 
natural  fissures,  as  to  attack  and  blowup  the  least  resisting 
masses.  Sometimes,  the  rock  is  prepared,  beforehand,  for 
splitting  in  a  certain  direction,  by  means  of  a  narrow  chan 
nel,  excavated  wath  the  small  hammer. 

The  quantity  of  gunpowder  should  be  proportional  to 
the  depth  of  the  hole,  and  the  resistance  of  the  rock  ;  and 
merely  sufficient  to  spht  it.  Any  thing  additional  w^ould 
serve  no  other  purpose  than  to  throw  the  fragments  about 
the  mine,  without  increasing  the  useful  effect.  Into  the 
holes  of  about  an  inch  and  a  quarter  diameter,  and  eigh- 
teen inches  deep,  only  two  ounces  of  gunpowder  are  put. 

It  appears,  that  the  effect  of  the  gunpowder  may  be 
augmented,  by  leaving  an  empty  space  above,  in  the  mid- 
dle of,  or  beneath,  the  cartridge.  In  the  mines  of  Sile- 
sia, the  consumption  of  gunpowder  has  been  eventually 
reduced,  without  diminishing  the  product  of  the  blasts, 
by  mixing  saw^dust  with  it,  in  certain  proportions.  The 
hole  has  also  been  filled  up  with  sand,  in  some  cases,  ac- 
cording to  Mr.  Jessop's  plan,  instead  of  being  packed 
with  stones,  which  has  removed  the  danger  of  the  tamp- 
ing operation.  The  experiments,  made  in  this  way,  have 
given  results  very  advantageous,  in  quarry  blasts,  with  great 
charges  of  gunpowder  ;  but  less  favorable,  in  the  small 
charges  employed  in  mines. 

Water  does  not  oppose  an  insurmountable  obstacle  to 
the  employment  of  gunpowder  ;  but  when  the  hole  cannot 
be  made  dry,  a  cartridge  bag,  impermeable  to  water,  must 
be  used,  provided  with  a  tube,  also  impermeable,  in  which 
:he  piercer  is  placed. 

After  the  explosion  of  each  mining  charge,  wedges  and 
levers  are  employed,  to  drag  away,  and  break  down,  what 
has  been  shattered. 

Wherever  the  rock  is  tolerably  hard,  the  use  of  gun 
powder  is  more  economical,  and  more  rapid,  than  any  tool' 
work,  and  is,  therefore,  always  preferred.     A  gallery,  for 
example,  a  yard  and  a  half  high,  and  a  yard  wide,  the 
25* 


294  APPENDIX. 

piercing  of  which,  by  the  hammer,  formerly  cost  from  five 
to  ten  pounds  sterling  the  running  yard,  in  Germany,  is 
executed,  at  the  present  day,  by  gunpowder,  at  from  two 
to  three  pounds.  When,  however,  a  precious  mass  of 
ore  is  to  be  detached  ;  when  the  rock  is  cavernous,  which 
nearly  nullifies  the  action  of  gunpowder  ;  or  when  there  is 
reason  to  apprehend  that  the  shock,  caused  by  the  explo- 
sion, may  produce  an  injurious  fall  of  rubbish,  hand-tools 
alone  must  be  employed. 

In  certain  rocks  and  ores,  of  extreme  hardness,  the  use, 
both  of  tools  and  gunpowder,  becomes  very  tedious  and 
costly.  Examples  to  this  effect  are  seen  in  the  mass  of 
quartz,  mingled  with  copper  pyrites,  worked  at  Rammels- 
burg,  in  the  Hartz  ;  in  the  masses  of  stanniferous  granite 
of  Geyer  and  Altenberg,  in  the  Erzgebirge  of  Saxony,  &c. 
In  these  circumstances,  fortunately  very  rare,  the  action 
of  fire  is  used  with  advantage,  to  diminish  the  cohesion  of 
the  rocks  and  the  ores.  The  employment  of  this  agent 
is  not  necessarily  restricted  to  these  difficult  cases.  It 
was  formerly  applied,  very  often,  to  the  working  of  hard 
substances  ;  but  the  introduction  of  gunpowder  into  the 
mining  art,  and  the  increase  in  the  price  of  wood,  occa- 
sion fire  to  be  little  used  as  an  ordinary  means  of  excava- 
tion, except  in  places, where  the  scantiness  of  the  popula- 
tion has  left  a  great  extent  of  forest-timber,  as  happens  at 
Kongsberg  in  Norway,  at  Dannemora  in  Sweden,  at  Fel- 
sobanya  in  Transylvania,  &c. 

The  action  of  fire  may  be  applied  to  the  piercing  of  a 
gallery,  or  to  the  advancement  of  a  horizontal  cut,  or  to 
the  crumbling  down  of  a  mass  of  ore,  by  the  successive 
upraising  of  the  roof  of  a  gallery  already  pierced.  In  any 
of  these  cases,  the  process  consists  in  forming  bonfires, 
the  flame  of  which  is  made  to  play  upon  the  parts  to  be 
attacked.  All  the  workmen  must  be  removed  from  the 
mine, during,  and  even  for  some  time  after,  the  combus- 
tion. When  the  excavations  have  become  sufficiently 
cool  to  allow  them  to  enter,  they  break  down  with  levers 
and  wedges,  or  even  by  means  of  gunpowder,  the  masses 
which  have  been  rent  and  altered  by  the  fire. 

To  complete  our  account  of  the  manner  in  which  man 


MINES.  295 

may  penetrate  into  the  interior  of  the  earth,  we  must  point 
out  the  form  of  the  excavations  that  he  should  make  in  it. 

In  mines,  three  principal  species  of  excavations  may 
be  distinguished,  viz.;  shafts,  galleries ^  and  the  cavities 
of  greater  or  less  magnitude,  which  remain  in  the  room 
of  the  old  workings. 

A  shaft,  or  pit,  is  a  prismatic,  or  cylindrical,  hollow 
space,  the  axis  of  which  is  either  vertical,  or  much  inclin- 
ed to  the  horizon.  The  dimension  of  the  pit,  which  is 
never  less  than  thirty-two  inches  in  its  narrowest  diameter, 
amounts, sometimes, to  several  yards.  Its  depth  may  ex- 
tei]yd  to  one  thousand  feet,  and  more.  Whenever  a  shaft 
is  opened,  means  must  be  provided  to  extract  the  rubbish, 
which  continually  tends  to  accumulate  at  its  bottom,  as 
well  as  the  waters,  which  may  percolate  down  into  it ;  as 
also  to  facilitate  the  descent  and  ascent  of  the  workmen 
For  some  time  a  wheel  and  axle,  erected  over  the  mouth 
of  the  opening,  which  serve  to  elevate  one  or  two  buckets, 
of  proper  dimensions,  may  be  sufficient  for  most  of  these 
purposes.  But  such  a  machine  becomes,  ere  long,  inad- 
equate. Horse-whims,  or  powerful  steam-engines,  must 
then  be  had  recourse  to  ;  and  effectual  methods  of  support 
must  be  employed,  to  prevent  the  sides  of  the  shaft  from 
crumbling,  and  falling  down. 

A  gallery  is  a  prismatic  space,  the  straight  or  winding 
axis  of  which  does  not  usually  deviate  much  from  the  hor- 
izontal line.  Two  principal  species  are  distinguished  ; 
the  galleries  of  elongation,  which  follow  the  direction  of 
a  bed,  or  a  vein  ;  and  the  transverse  galleries,  which  in- 
tersect this  direction  under  an  angle,  not  much  different 
from  ninety  degrees.  The  most  ordinary  dimensions  of 
galleries  are  a  yard  wide,  and  two  yards  high  ;  but  many, 
still  larger,  may  be  seen,  transversing  thick  deposites  of 
ore.  There  are  few,  whose  width  is  less  than  twenty-four 
inches,  and  height  less  than  forty;  such  small  drifts  serve 
merely  as  temporary  expedients  in  workings.  Some  gal- 
leries are  several  leagues  in  length.  We  shall  cescribe, 
in  the  sequel,  the  means  which  are,  for  the  most  part, 
necessary  to  support  the  roof  and  the  walls.  The  rubbish 
is  removed  by  wagons,  or  wheel-barrows,  of  various  kinds; 


296  APPENDIX. 

It  is  impossible  to  advance  the  boring  of  a  shaft,  or  gal 
lery,  beyond  a  certain  rate  ;  because  only  a  limited  set  of 
workmen  can  be  made  to  bear  upon  it. 

There  are  some  galleries  which  have  taken  more  than 
thirty  years  to  perforate.  The  only  expedient  for  accel- 
erating the  advance  of  a  gallery,  is,  to  commence,  at  sev- 
eral points  of  the  line  to  be  pursued,  portions  of  galleries, 
which  may  be  joined  together  on  their  completion. 

Whether  tools,  or  gunpowder,  be  used,  in  making  the 
excavations,  they  should  be  so  applied,  as  to  render  the 
labor  as  easy  and  quick  as  possible,  by  disengaging  the 
mass  out  of  the  rock,  at  two  or  three  of  its  faces.  The 
effect  of  gunpowder,  wedges,  or  picks,  is  then  much  more 
powerful.  The  greater  the  excavation,  the  more  impor- 
tant is  it  to  observe  this  rule.  With  this  intent,  the  work- 
ing is  disposed  in  the  form  of  steps,  (gradins,)  placed 
like  those  of  a  stair  ;  each  step  being  removed,  in  succes- 
sive portions,  the  whole  of  which,  except  the  last,  are 
disengaged  on  three  sides,  at  the  instant  of  their  being  at- 
tacked. 

The  substances  to  be  mined  occur  in  the  bosom  of 
the  earth,  under  the  form  of  alluvial  deposits,  beds,  pipe- 
veins  or  masses,  threads  or  small  veins,  and  rake-veins. 

When  the  existence  of  a  deposit  of  ore  is  merely  sus- 
pected, without  positive  proofs,  recourse  must  be  had  to 
labors  of  research,  in  order  to  ascertain  the  richness,  na- 
ture, and  disposition,  of  a  supposed  mine.  These  are 
divided  into  three  kinds  ;  open  workings,  subterranean 
workings,  and  boring  operations. 

1 .  The  working  by  an  open  trench  has  for  its  object 
to  discover  the  outcropping,  or  basset  edges  of  strata,  or 
veins.  It  consists  in  opening  a  fosse  of  greater  or  less 
width,  which,  after  removing  the  vegetable  mould,  the 
alluvial  deposits,  and  the  matters  disintegrated  by  the  at 
mosphere,  discloses  the  native  rocks,  and  enables  us  to 
distinguish  the  beds,  which  are  interposed,  as  well  as  the 
veins  which  traverse  them  ;  the  trench  ought  always  to  be 
opened  in  a  direction  perpendicular  to  the  line  of  the  sup 
posed  deposit.     This  mode  of  investigation  costs  little 


DEPTH  OP  MINES.  297 

Dut  it  seldom  gives  much  insight.     It  is  chiefly  employed 
for  verifying  the  existence  of  a  supposed  bed,  or  vein. 

The  subterranean  workings  afibrd  much  more  satisfac- 
tory knowledge.  They  are  executed  by  different  kinds 
of  perforations  ;  viz.  by  longitudinal  galleries^  hollowed 
out  of  the  mass  of  the  beds  or  veins  themselves,  in  fol- 
lowing their  course  ;  by  transverse  galleries,  pushed  at 
right  angles  to  the  direction  of  the  veins  ;  by  inclined 
shafts,  which  pursue  the  slope  of  the  deposits,  and  are 
excavated  in  their  mass  ;  or,  lastly,  hy  perpendicular  pits. 

If  a  vein  or  bed  unveils  itself  on  .the  flank  of  a  moun- 
tain, it  may  be  explored,  according  to  the  greater  or  less 
slope  of  its  inclination,  either  by  a  longitudinal  gallery, 
opened  in  its  mass  from  the  outcropping  surface,  or  by 
a  transverse  gallery,  falling  upon  it  in  a  certain  point, 
from  which  either  an  oblong  gallery,  or  a  sloping  shaft, 
may  be  opened. 

If  our  object  be  to  reconnoitre  a  highly  inclined  stra- 
tum, or  a  vein  in  a  level  country,  we  shall  obtain  it,  with 
sufficient  precision,  by  means  of  shafts,  eight  or  ten  yards 
deep,  dug  at  thirty  yards  distance  from  one  another,  ex- 
cavated in  the  mass  of  ore,  in  the  direction  of  its  depo- 
sit. If  the  bed  is  not  very  much  inclined,  only  forty-five 
degrees,  for  example,  vertical  shafts  must  be  opened  in 
the  direction  of  its  roof,  or  of  tffe  superjacent  rocky  stra 
tum,  and  galleries  must  be  driven  from  the  points  in 
which  they  meet  the  ore,  in  the  line  of  its  direction. 

When  the  rocks,  w^hich  cover  valuable  minerals,  are  not 
of  very  great  hardness,  as  happens  generally  with  the  coal 
formation,  with  pyritous  and  aluminous  slates,  sal  gem, 
and  some  other  minerals  of  the  secondary  strata,  the  bor- 
er is  employed  with  advantage,  to  ascertain  their  nature. 
This  mode  of  investigation  is  economical,  and  gives,  in 
such  cases,  a  tolerably  exact  insight  into  the  riches  of  the 
interior.  The  method  of  using  the  borer  has  been  de- 
scribed under  Artesian  Wells. —  Ure''s  '  Diet.  ofJlrts,'^  Sf^c. 

III. — Depth  of  Mines. 

At  the  third  meeting  of  the  British  Association,  Mr. 
Taylor  exhibited  a  section,  showing  the  depths  of  shafts 


298  APPENDIX. 

of  the  deepest  mines  in  the  world,  and  their  position  in 
relation  to  the  level  of  the  sea. 

The  absolute  depths  of  the  principal  ones  were : 

Feet. 

1.  The  shaft,  called  Roehrobichel,  at  the  Kitspiihl  mine, 

in  the  Tyrol, 2764 

2.  At  the  Sampson  mine,  at  Andreasberg,  in  the  Hartz, ....  2230 

3.  At  the  Valenciana  mine,  at  Guanaxuato,  Mexico, 1770 

4.  Pearce's  shaft,  at  the  Consolidated  mines,  Cornwall, ....  1464 

5.  At   Wheal  Abraham  mine,  Cornwall, 1452 

6.  At  Dolcoath  mine,  Cornwall, 1410 

7.  At  Ecton  mine,  Staffordshire, 1380 

8.  Woolf's  shaft,  at  the  Consolidated  mines, 1350 

These  mines  are,  however,  very  differently  situated, 
with  regard  to  their  distance  from  the  centre  of  the  earth  ; 
as  the  last  on  the  list,  Woolf's  shaft,  at  the  Consolidated 
mines,  has  twelve  hundred  and  thirty  feet  of  its  depth  be- 
low the  surface  of  the  sea  ;  while  the  bottom  of  the  shaft 
of  Valenciana,  in  Mexico,  is  near  six  thousand  feet  in 
absolute  height  above  the  tops  of  the  shafts  in  Cornwall. 
The  bottom  of  the  shaft,  at  the  Sampson  mine,  in  the 
Hartz,  is  but  a  few  fathoms  under  the  level  of  the  ocean ; 
and  this,  and  the  deep  mine  of  Kitspiihl,  form,  therefore, 
intermediate  links  between  those  of  jSlexico  and  Cornwall. 

Mr.  Taylor  stated,  that,  taking  the  diameter  of  the 
earth  at  eight  thousand  miles,  and  the  greatest  depth  un- 
der the  surface  of  the  se^  being  twelve  hundred  and  thir- 
ty feet,  or  about  one  fourth  of  a  mile,  it  follows,  that  we 
have  only  penetrated  to  the  extent  of  ^^^-^tj  P^^^t  of  the 
earth's  diameter. 

IV. — Canals  in  the  United  States. 

The  Americans  have  not  rested  satisfied  with  the  nat- 
ural inland  navigation  afforded  by  their  rivers  and  lakes, 
nor  made  the  bounty  of  Nature  a  plea  for  idleness,  or  want 
of  energy  ;  but,  on  the  contrary,  they  have  been  zealously 
engaged  in  the  work  of  internal  improvement ;  and  their 
country  now  numbers,  among  its  many  wonderful  artifi- 
cial lines  of  communication,  a  mountain  rail-way,  which, 
in  boldness  of  design,  and  difficulty  of  execution,  I  can 
compare  to  no  modern  works  I  have  ever  seen,  except- 
ng,  perhaps,  the  passes  of  the  Simplon,  and  MontCenis, 


CANALS  IN  THE  UNITED  STATES.        299 

in  Sardinia  ;  but  even  these  remarkable  passes,  viewed 
as  engineering  works,  did  not  strike  me  as  being  more 
wonderful  than  the  Alleghany  rail-way,  in  the  United 
States. 

The  objects,  to  which  that  enterprising  people  have 
chiefly  directed  their  exertions  for  the  advancement  of  their 
country  in  the  scale  of  civilization,  are,  the  removal  of  ob- 
s-rructions  in  navigable  rivers  ;  the  junction  of  different 
tracts  of  natural  navigation  ;  the  connection  of  large  towns  ; 
and  the  formation  of  lines  of  communication  from  the  At- 
lantic ocean  to  the  great  lakes,  and  the  valleys  of  the 
Mississippi,  Missouri,  and  Ohio.  The  number  and  ex- 
tent of  canals  and  rail-ways  which  they  have  executedj  in 
effecting  these  important  objects,  sufficiently  prove,  that 
their  exertions,  during  the  short  time  they  have  been  so 
engaged,  have  been  neither  small  nor  ill-directed.  The 
aggregate  length  of  the  canals,  at  present  in  operation  in 
the  United  States  alone,  amounts  to  upwards  of  two  thou- 
sand seven  hundred  miles,  and  that  of  the  rail-ways,  already 
completed,  to  sixteen  hundred  miles.  Nor  are  the  labors 
of  the  people  at  an  end  ;  for,  even  now,  there  are  no  few- 
er than  thirty-three  rail-ways  in  an  unfinished  state,  whose 
aggregate  length,  when  completed,  will  amount  to  upwards 
of  two  thousand  five  hundred  miles. 

The  zeal  with  which  the  Americans  undertake,  and  the 
rapidity  with  which  they  carry  on,  every  enterprise,  which 
has  the  enlargement  of  their  trade  for  its  object,  cannot 
fail  to  strike  all,  w^ho  visit  the  United  States,  as  a  charac- 
teristic of  the  nation.  Forty  years  ago,  that  country  was 
almost  without  a  lighthouse,  and  now,  no  fewer  than  two 
hundred  are  nighdy  exhibited  on  its  coast ;  thirty  years 
ago,  it  had  but  one  steamboat,  and  one  short  canal,  and 
now,  its  rivers  and  lakes  are  navigated  by  between  five  and 
six  hundred  steamboats,  and  its  canals  are  upwards  of  two 
thousand  seven  hundred  miles  in  length  ;  ten  years  ago, 
there  were  but  three  miles  of  rail-way  in  the  country,  and 
now,  there  are  no  less  than  sixteen  hundred  miles  in  oper- 
ation." These  facts  appear  much  more  wonderful,  when 
it  is  considered,  that  many  of  these  great  lines  of  commu- 
nication are  carried  for  miles  in  a  trough,  as  it  were,  cut 


300  APPENDIX. 

through  thick  and  almost  impenetrable  forests,  where  it  is 
no  uncommon  occurrence  to  travel  for  a  whole  clay,  with- 
out encountering  a  village,  or  even  a  house,  excepting, 
perhaps,  a  few  log-huts,  inhabited  by  persons  connected 
with  the  works. 

The  routes  of  the  principal  canals  and  rail-roads  in 
North  America  are  not  wholly  confined  to  the  seaward  and 
more  thickly-peopled  States,  but  extend  far  into  the  in- 
terior. The  stupendous  canals,  which  have  already  been 
executed,  enable  vessels,  suited  to  the  inland  navigation 
of  the  country,  to  pass  from  the  Gulf  of  St.  Lawrence  to 
the  Gulf  of  Mexico,  and  also  from  the  city  of  j\ew  York 
to  Quebec,  on  the  St.  Lawrence,  or  to  New  Orleans,  on 
the  Mississippi,  without  encountering  the  dangers  of  the 
Atlantic  ocean.  But,  that  the  reader  may  be  able  fully 
to  understand  the  nature  of  lines  of  inland  navigation,  so 
enormous,  I  shall  give,  in  detail,  the  route  from  New 
York  to  New  Orleans,  which  is  constantly  made  by  per 
sons  travelling  between  those  places. 

Miles. 
From  New  York  to  Albany,  by  the  River  Hudson,  the  dis- 
tance is,         .......  .  150 

♦'     Albany  to  Buffalo,  by  the  Erie  Canal,  .         .         .         .363 

♦'     Buffalo  to  Cleveland,  by  Lake  Erie,  .  ...         210 

"     Cleveland  to  Portsmouth,  by  the  Ohie  Canal,         .  .     309 

■ '     Portsmouth  to  New  Orl^ns,  by  the  Ohio  and  Mississippi 

Rivers,  . 1670 

Total  distance,       .         .       2702 

This  extraordinary  inland  journey,  of  no  less  than  two 
thousand  seven  hundred  and  two  miles,  is  performed  en- 
tirely by  means  of  water-communication  ;  six  hundred 
and  seventy-two  miles  of  the  journey  are  performed  on 
canals,  and  the  remaining  two  thousand  and  thirty  miles 
of  the  route  is  river  and  lake  navigation. 

The  internal  improvements  of  the  United  States  are 
placed  under  the  management  either  of  the  Legislatures  of 
the  States,  in  which  the  works  are  situate,  or  of  joint- 
stock  companies.  The  works  constructed  by  the  Legis- 
latures of  the  States,  are  called  State  Works,  and  are 
conducted  by  commissioners,  chosen  from  the  different 


CANALS   IN  THE    UNITED   STATES.  301 

Legislatures,  who  publish  annual  reports  on  the  works 
committed  to  their  charge.  The  joint-stock  companies, 
on  the  other  hand,  are  composed  of  private  individuals, 
who  receive  a  charter  from  the  Government,  investing 
them  with  powe'r  to  execute  the  work,  and  afterwards  to 
conduct  the  affairs  and  transact  the  business  of  the  com- 
pany. The  public  works  in  the  British  dominions  in 
North  America  have  been  executed,  partly,  at  the  ex- 
pense, and  under  the  direction,  of  the  British  Govern- 
ment, and  partly,  by  companies  of  private  individuals. 

It  is  believed  that  canals,  which  were,  until  very  lately, 
the  only  mode  of  conveyance  employed  in  North  Ameri- 
ca, were  in  use  in  Egypt,  China,  Ceylon,  Italy,  and  Hol- 
land, before  the  Christian  era  ;  but  the  period,  at  which 
the  first  artificial  water-communication  w^as  formed,  and 
the  country,  in  which  the  construction  of  a  canal  was  first 
attempted,  are  equally  unknown.  The  earliest  canal  con- 
structed in  France  was  the  Languedoc,  connecting  the 
Bay  of  Biscay  with  the  Mediterranean  Sea,  w^hich  was 
completed  in  the  year  1681  ;  and  the  first  formed  in 
Great  Britain  was  that  of  Sankey  Brook,  in  Lancashire, 
completed  in  1760.  Several  short  canals  were  made, 
for  improving  the  river  navigation,  in  the  United  States, 
about  the  end  of  the  last  century  ;  but  the  first  work  of 
any  importance,  in  that  countr^jr,  was  the  Santee  canal, 
in  the  State  of  South  Carolina,  which  was  opened  in  the 
year  1802  ;  and  the  first,  in  the  British  dominions  in  Amer- 
ica, was  the  Lachine  canal,  in  Lower  Canada,  opened  in 
the  year  1821.  At  the  end  of  this  chapter  is  a  table  of 
the  principal  canals  in  the  United  States.  The  table, 
which  is  compiled  from  the  American  a/manacs,  and  the 
annual  reports  of  the  canal  commissioners,  contains  the 
names  of  all  the  canals  of  any  importance,  now  in  opera- 
tion in  the  country  ;  together  with  such  information,  regard- 
ing their  size  and  expense,  as  these  documents  contain. 

The  great  length  of  many  of  the  A-merican  canals  is 
one  remarkable  feature  in  these  astonishing  works.  In 
this  respect,  they  far  surpass  any  thing  of  the  kind  hith- 
erto constructed  in  Europe.  The  longest  canal  in  Eu- 
rope is  the  Languedoc,  which  has  a  course  of  one  hun- 
II.  26  XII. 


302  APPENDIX. 

dred  and  forty-eight  miles  ;  and  the  most  extensive  in  the 
United  States  is  the  Erie  canal,  which  is  no  less  than 
three  hundred  and  sixty-three  miles  in  length.  But  the 
cross-sectional  area  of  the  American  canals  is  by  no  means 
so  great  as  that  of  many  in  Europe.  The  North  Holland 
Ship  canal,  for  example,  between  the  Zuyder  Zee,  at 
Amsterdam,  and  the  Holder,  which  I  lately  visited,  has  a 
larger  cross-sectional  area,  than  any  other  European  work 
of  the  same  description.  It  measures  one  hundred  and 
twenty-four  feet  six  inches,  at  the  water-line,  and  affords 
sufficient  breadth  to  allow  large  vessels  to  pass  each  other 
with  perfect  ease.  It  is  fifty-six  feet  in  breadth,  at  the 
bottom,  and  has  a  depth  of  water  of  no  less  than  twenty- 
one  feet.  This  remarkable  canal,  which  is  nearly  fifty 
miles  in  length,  undoubtedly  ranks  as  one  of  the  greatest 
works  of  the  kind  that  has  ever  been  executed.  It  was 
constructed  for  the  purpose  of  facihtating  the  passage  of 
vessels  to  and  from  the  port  of  Amsterdam  ;  and,  by  means 
of  the  sheltered  inland  passage  which  it  affords,  the  intri- 
cate and  dangerous  navigation  of  the  Zuyder  Zee  is  avoid- 
ed. At  the  time  when  canals  were  introduced  into  Amer- 
ica, however,  the  trade  of  the  country  was  small,  and  did 
not  warrant  the  expenditure  of  large  sums  of  money  in 
their  construction,  the  chief  object  being  to  form  a  com- 
munication, with  as  little  loss  of  time,  or  outlay  of  capital, 
as  might  be  consistent  with  a  due  regard  for  the  safety  and 
stability  of  the  work.  It  is  not  to  be  expected,  therefore, 
that  the  American  works,  although  on  an  extensive  scale, 
should  be  constructed  in  the  same  spacious  style  as  those 
of  older  and  more  opulent  countries.  The  dimensions  of 
many  of  the  canals  in  the  United  States  are  no-w  found 
to  be  inconveniently  small,  for  the  increased  traffic  which 
they  have  to  support ;  and  the  great  Erie  canal,  as  well 
as  some  others,  is  at  present  undergoing  extensive  altera- 
tions, by  which  its  breadth  will  be  increased  from  forty  to 
sixty  feet,  and  its  depth  from  four  to  seven  feet.  It  is 
doubtful  whether  the  increased  depth  will,  on  the  whole, 
j)rove  advantageous,  especially  for  quick  transport.  Ac- 
cording to  Mr.  Russell,  the  velocity  of  the  wave  due  to  a 
depth  of  four  feet,  making  allowance  for  the  sloping  sides 


CANALS   IN  THE  UNITED   STATES.  303 

of  the  canal,  is  about  seven  miles  an  hour  ;  and  if  the  boat 
is  dragged  in  the  top  of  the  wave,  the  horses  must  travel 
at  somewhat  more  than  this  rate,  in  order  to  keep  before 
Jt.  If,  on  the  other  hand,  the  depth  of  the  canal  be  seven 
feet,  the  velocity  of  the  wave  will  be  about  nine  miles  an 
hour  ;  a  speed  which  it  would  be  difficult  for  horses  regular- 
ly to  keep  up.  The  boat  would,  consequently,  travel  at 
a  less  speed  than  the  wave,  which  is  shown  by  Mr.  Rus- 
sell, in  his  '  Researches  in  Hydrodynamics,'  to  be  very 
disadvantageous. 

English  and  American  engineers  are  guided  by  the 
same  principles  in  designing  their  works  ;  but  the  differ- 
ent nature  of  the  materials  employed  in  their  construc- 
tion, and  the  climates  and  circumstances  of  the  two  coun- 
tries, naturally  produce  a  considerable  dissimilarity  in  the 
practice  of  civil-engineers  in  England  and  America.  At 
the  first  view,  one  is  struck  with  the  temporary  and  ap- 
parently unfinished  state  of  many  of  the  American  w^orks, 
and  is  very  apt,  before  inquiring  into  the  subject,  to  im- 
pute to  want  of  ability  what  turns  out,  on  investigation, 
to  be  a  judicious  and  ingenious  arrangement  to  suit  the 
circumstances  of  a  new  country,  of  which  the  climate  is 
severe, — a  country, where  stone  is  scarce,  and  wood  is 
plentiful,  and  where  manual  labor  is  very  expensive.  It 
is  vain  to  look  to  the  American  works  for  the  finish,  that 
characterizes  those  of  France,  or  the  stability,  for  which 
those  of  Britain  are  famed.  Undressed  slopes  of  cut- 
tings and  embankments,  roughly-built  rubble-arches,  stone 
parapet-walls  coped  with  timber,  and  canal-locks  whol- 
ly constructed  of  that  material,  every  where  offend  the 
eye  accustomed  to  view  European  workmanship.  But  it 
must  not  be  supposed  that  this  arises  from  want  of  knowl- 
edge of  the  principles  of  engineering,  or  of  skill  to  do 
them  justice  in  the  execution.  The  use  of  wood,  for 
example,  which  may  be  considered,  by  many,  as  wholly 
inapplicable  to  the  construction  of  canal-locks,  where  it 
must  not  only  encounter  the  tear  and  wear  occasioned  by 
the  lockage  of  vessels,  but  must  be  subject  to  the  destruc 
tive  consequences  of  alternate  immersion  in  water  and 
exposure  to  the  atmosphere,  is  yet  the  result  of  delioer- 


304  APPENDIX. 

ate  judgement.  The  Americans  have,  in  many  cases, 
been  induced  to  use  the  material  of  the  country,  ill  adapt- 
ed though  it  be,  in  some  respects,  to  the  purposes  to 
which  it  is  applied,  in  order  to  meet  the  wants  of  a  ris- 
ing community,  by  speedily,  and  perhaps  superficially, 
completing  a  work  of  importance,  which  would  otherwise 
be  delayed,  from  a  want  of  the  means  to  execute  it  in  a 
more  substantial  manner  ;  and,  although  the  works  are 
wanting  in  finish,  and  even  in  sohdity,  they  do  not  fail 
for  many  years  to  serve  the  purposes  for  which  they  were 
constructed,  as  efficiently  as  works  of  a  more  lasting  de- 
scription. 

When  the  wooden  locks  on  any  of  the  canals  begin  to 
show  symptoms  of  decay,  stone  structures  are  generally 
substituted  ;  and  materials,  suitable  for  their  erection,  are 
with  ease  and  expedition  conveyed  from  the  part  of  the 
country  where  they  are  most  abundant,  by  means  of  the 
canal  itself  to  which  they  are  to  be  applied  ;  and  thus 
the  less  substantial  work  ultimately  becomes  the  means 
of  facilitating  its  own  improvement,  by  affording  a  more 
easy,  cheap,  and  speedy  transport  of  those  durable  and 
expensive  materials,  without  the  use  of  which,  perfectioi 
is  unattainable. 

One  of  the  most  important  advantages  of  constructing 
the  locks  of  canals,  in  new  countries,  such  as  America, 
of  wood,  unquestionably  is,  that,  in  proportion  as  improve 
ment  advances,  and  greater  dimensions,  or  other  changes, 
are  required,  they  can  be  introduced  at  little  cost,  and 
without  the  mortification  of  destroying  expensive  and 
substantial  works  of  masonry.  Some  of  the  locks  on 
the  great  Erie  canal  are  formed  of  stone  ;  but,  had  they 
all  been  made  of  wood,  it  would,  in  all  probability,  have 
been  converted  into  a  ship-canal, long  ago. 

But  the  locks  are  not  the  only  parts  of  the  American 
canals  in  which  wood  is  used.  Aqueducts,  over  ravines 
or  rivers,  are  generally  formed  of  large  wooden  troughs, 
resting  on  stone  pillars  ;  and  even  more  temporary  expe- 
dients have  been  chosen,  the  ingenuity  of  which  can  hard- 
ly fail  to  please  those  who  view  them  as  the  means  of 
carrying  on  improvements,  which,  but  for  such  contriv- 


CANALS   IN  THE  UNITED   STATES.  305 

ances,  might  be  stopped  by  the  want  of  funds  necessary 
to  complete  them. 

Mr.  M'Taggart,  the  resident  engineer  for  the  Rideau 
canal  in  Canada,  gave  a  good  example  of  the  extraordi- 
nary expedients  often  resorted  to,  by  suggesting  a  very 
novel  scheme  for  carrying  that  work  across  a  thickly 
wooded  ravine,  situate  in  a  part  of  the  country  where 
materials  for  forming  an  embankment,  or  stone  for  build- 
ing the  piers  of  an  aqueduct,  could  not  be  obtained  but 
at  a  great  expense.  The  plan  consisted  of  cutting  across 
the  large  trees  in  the  line  of  the  works,  at  the  level  of 
the  bottom  of  the  canal,  so  as  to  render  them  fit  for  sup- 
porting a  platform  on  their  trunks,  and  on  this  platform  the 
trough  containing  the  water  of  the  canal  was  intended  to 
rest.  I  am  not  aware  whether  this  plan  was  carried  into 
effect  ;  but  it  is  not  more  extraordinary  than  many  of  the 
schemes  to  which  the  Americans  have  resorted,  in  con- 
structing their  pubhc  works  ;  and  the  great  traffic  sus- 
tained by  many  of  them,  notwithstanding  the  temporary 
and  hurried  manner  in  which  they  are  finished,  is  truly 
wonderful.  The  number  of  boats  navigating  the  Erie 
canal,  in  1836,  was  no  less  than  three  thousand  one  hun- 
dred and  sixty-seven,  and  the  average  number  of  lockages, 
one  hundred  and  eighteen  per  day  ;  facts  which  clearly 
prove  the  efficiency,  as  well  as  the  utihty,  of  the  work. 

With  the  exception  of  some  few  works,  in  the  most 
southern  States  of  the  Union,  the  artificial  navigation  of 
North  America,  as  well  as  that  of  the  northern  rivers 
and  lakes,  is  completely  suspended  during  a  period  of 
from  three  to  five  months,  every  year.  During  that  time, 
the  water  is  always  withdrawn  from  the  canals  and  feed- 
ers. This  precaution  is  absolutely  necessary,  as  the  in- 
tense frost, with  which  the  country  is  then  visited,  very 
soon  proves  destructive  to  the  locks  and  aqueducts,  by 
the  expansion  of  the  water,  which,  if  permitted  to  re- 
main in  them,  is  speedily  converted  into  a  mass  of  ice. 

The  rate  of  travelling,  which  has   been   adopted   on 

the  American  canals,  the  charges  for  the  conveyance  of 

passengers  and  goods,  and  the  general  laws  for  regulating 

canal  transport,  are  fixed  by  the  commissioners  who  have 

26* 


306  APPENDIX. 

charge  of  the  different  works,  and  are  not  exactly  the 
same  in  every  State.  The  following  observations,  how- 
ever, regarding  the  mode  of  travelling  on  the  Pensylva- 
nia  State  canals,  are  generally  applicable  to  all  others  in 
the  country. 

The  tolls  paid  to  the  State,  by  the  persons  who  have 
boats  on  the§e  canals,  are  three  halfpence  per  mile  for 
each  boat,  and  three  farthings  per  mile  for  each  passenger 
conveyed  in  them.  The  passenger-boats  vary  from  twelve 
to  fifteen  feet  in  breadth,  and  are  eighty  feet  in  length  ; 
the  large-sized  boats  weigh  about  twenty  tons,  and  cost 
£250  each,  and,  when  loaded  with  a  full  complement  of 
passengers,  draw  twelve  inches  of  w^ater.  They  are 
dragged  by  three  horses  at  once,  which  run  ten-mile  sta- 
ges. The  length  of  the  tow-hne,  generally  used,  is  about 
one  hundred  and  fifty  feet,  and  the  rate  of  travelling  is 
from  four  to  four  and  a  half  miles  per  hour. 

The  works,  which  have  been  employed  in  forming 
the  inland  lines  of  water-communication  in  America,  are 
of  two  kinds,  called  slackwater-navigation,  and  canals. 
The  slackw^ater-navigation  is  the  more  simple  of  these 
operations,  and  can  generally  be  executed  at  less  expense. 
It  consists  in  improving  the  navigation  of  a  river  by  the 
erection  of  dams,  or  mounds,  built  in  the  stream,  which 
have  the  effect  of  damming  up  the  water,  and  increasing 
its  depth.  If  there  be  not  a  great  fall  in  the  bed  of  the 
river,  a  single  dam  often  produces  a  stagnation  in  the  run 
of  the  water,  extending  for  many  miles  up  the  river,  and 
forming  a  spacious  navigable  canal.  The  tow-path  is 
formed  along  the  margin  of  the  river,  and  is  elevated  above 
the  reach  of  flood- water.  The  dams  are  passed  by  means 
of  locks,  such  as  are  used  in  canals.  This  method  of 
forming  water-communication,  has  been  extensively  and 
successfully  introduced  in  America,  where  limited  means, 
and  abundance  of  rivers,  rendered  it  peculiarly  applicable. 
One  of  the  most  extensive  works,  on  this  principle,  in  the 
country,  was  constructed  by  the  Schuylkill  Navigation 
Company,  in  the  State  of  Pennsylvania,  and  consisted  in 
damming  up  the  water  of  the  river  Schuylkill.  It  ex- 
tends from  Philadelphia  to  Readii^,  and  is  situate  in  the 


CANALS   IN  THE   UNITED   STATES.  307 

lieart  of  a  country  abounding  in  coal,  from  the  transport 
of  which,  the  Company  derives  its  chief  revenue.  It  is 
one  hundred  and  eight  miles  in  length,  and  its  construc- 
tion cost  about  .£500,000.  This  line  of  navigation  is 
formed  by  numerous  dams  thrown  across  the  stream,  with 
twenty-nine  locks,  which  overcome  a  fall  of  six  hundred 
and  ten  feet.  It  is  navigated  by  boats  of  from  fifty  to 
sixty  tons  burden.  These  dams  are  constructed  some- 
what on  the  same  principle  as  that  erected  on  the  Schuyl- 
kill, at  Fairmount  Water-works,  near  Philadelphia. 

One  great  objection,  to  this  mode  of  forming  inland 
navigation,  is  the  necessity  of  constructing  works  of  great 
strength,  sufficient  to  enable  them  to  withstand  the  floods 
and  ice,  to  which  they  are  exposed,  and  by  which  they  are 
very  apt  to  be  damaged,  or  even  carried  away.  Acci- 
dents of  this  kind,  however,  may  be  in  a  great  measure 
guarded  against,  by  making  a  judicious  selection  of  situa- 
tions for  the  dams  and  locks,  and  placing  them  in  such  a 
manner  in  the  bed  of  the  river,  that  the  current  may  act 
on  them  in  the  direction  least  detrimental  to  their  sta- 
bility, as  has  been  done  in  the  dam  at  Fairmount  Water- 
works, just  alluded  to. 

The  number  of  boats,  which  passed  through  the  locks 
of  the  Schuylkill  navigation,  in  1836,  was  twenty-four 
thousand  four  hundred  and  seventy,  the  tolls  on  which 
amounted  to  £14,043.  The  various  articles  taken  up 
the  river,  during  that  year,  weighed  sixty-one  thousand 
and  seventy-nine  tons,  and  those  brought  towards  the  sea, 
five  hundred  and  seventy  thousand  and  ninety-four  tons,  of 
which  four  hundred  and  thirty-two  thousand  and  forty-five 
tons  were  anthracite  coal,  from  the  State  of  Pennsylvania. 

Slackwater-navigation  also  occurs  at  intervals  on  many 
of  the  great  lines  of  canal.  About  seventy-eight  miles  of 
ihe  Rideau  canal,  in  Canada,  are  formed  in  this  way  ;  and 
in  the  United  States,  it  is  met  with  on  the  Erie,  Oswego, 
Pennsylvania,  Frankston,  Lycoming,  and  Lehigh  canals. 
The  works  which  have  been  executed,  in  forming  most 
of  the  water-communications,  in  America,  however,  are 
not  generally  of  the  slackwater  kind,  but  resemble  the 
canals  in  use  in  Europe,  being,  in  fact,  artificial  trenches 


308  APPENDIX. 

or  troughs,  with  locks  to  enable  vessels  to  pass  from  one 
evel  to  another.  The  locks  are  furnished  with  boom-- 
gates,  which  are  opened  and  shut  by  a  long  lever  fixed  to 
the  tops  of  the  quoin  and  mitre  posts.  The  sluices,  by 
which  the  water  is  admitted  into  the  locks,  are  placed  in 
the  lower  part  of  the  gates.  They  are,  in  general,  com- 
mon hinge-sluices,  opened  by  means  of  a  rod  extending 
to  the  top  of  the  gates,  and  worked  by  a  crank  handle. 

The  canals  of  this  construction,  in  the  United  States, 
are  so  very  numerous,  and  resemble  each  other  so  much, 
that  I  do  not  consider  it  necessary  to  give  a  detailed  de- 
scription of  the  various  works  which  have  been  executed 
on  all  of  them,  but  shall  content  myself  with  giving  a  briel 
sketch  of  the  Erie  canal,  which  was  the  first  in  America, 
on  which  the  conveyance  of  passengers  was  attempted, 
and  is  the  longest  canal  in  the  world,  regarding  wdiich  we 
possess  accurate  information. 

The  Erie  canal  was  commenced  in  1817,  and  com- 
pleted in  1825.  The  main  line,  leading  from  Albany,  on 
the  Hudson,  to  Buffalo,  on  Lake  Erie,  measures  363 
miles  in  length,  and  cost  about  ^1,400,000  sterling. 
The  Champlain,  Oswego,  Chemung,  Cayuga,  and  Crook- 
ed Lake,  canals,  and  some  others,  join  the  main  line, 
and,  including  these  branch  canals,  it  measures  five  hun- 
dred and  forty-three  miles  in  length,  and  cost  upwards 
of  £2,300,000.  This  canal  is  forty  feet  in  breadth,  at 
the  water  line,  twenty-eight  feet,  at  the  bottom,  and  four 
fpet  in  depth.  Its  dimensions  have  proved  too  small  for 
the  extensive  trade  which  it  has  to  support,  and  workmen 
are  now  employed  in  raising  its  banks,  so  as  to  increase 
the  depth  of  water  to  seven  feet,  and  the  extreme  breadth 
of  the  canal  to  sixty  feet.  The  country  through  which 
it  passes,  is  admirably  suited  for  canal-navigation,  and 
there  are  only  eighty-four  locks  on  the  main  line.  These 
locks  are  each  ninety  feet  in  length,  and  fifteen  in  breadth, 
and  have  an  average  lift  of  eight  feet  two  inches.  The 
total  rise  and  fall  is  six  hundred  and  ninety-two  feet. 
The  tow-path  is  elevated  four  feet  above  the  level  of  the 
water,  and  is  ten  feet  in  breadth.  The  Erie  canal  begins 
at  Buffalo,  on  Lake  Erie,  and  extends  for  a  distance  of 


CANALS   IN  THE   UNITED  STATES.  309 

about  ten  miles  along  the  banks  of  Lake  Erie  and  the 
river  Niagara,  as  far  as  Tonawanda  creek.  By  means 
of  the  slackwater-navigation,  formerly  described,  the 
channel  of  the  Tonawanda  is  rendered  navigable  for  the 
distance  of  twelve  miles,  and  the  canal  is  then  carried 
through  a  deep  cutting,  extending  seven  and  a  half  miles, 
to  Lockport.  Here  it  descends  sixty  feet,  by  means  of 
five  locks  excavated  in  solid  rock,  and  afterwards  pro- 
ceeds, on  a  uniform  level,  for  a  distance  of  sixty-three 
miles,  to  Genesee  river,  over  which  it  is  carried  on  an 
aqueduct  having  nine  arches,  of  fifty  feet  span,  each. 
Eight  and  a  half  miles  from  this  point,  it  passes  over  the 
Cayuga  marsh,  on  an  embankment  two  miles  in  length,  and, 
in  some  places,  seventy  feet  in  height.  It  then  passes 
through  Lakeport  and  Syracuse,  and,  at  this  place,  the 
"  long  level"  commences,  which  extends  for  a  distance 
of  no  less  than  sixty-nine  and  a  half  miles,  to  Frankfort, 
without  an  intervening  lock.  After  leaving  Frankfort, 
the  canal  crosses  the  river  Mohawk,  first  by  an  aqueduct, 
of  seven  hundred  and  forty-eight  feet  in  length,  supported 
on  sixteen  piers,  elevated  twenty-five  feet  above  the  sur- 
face of  the  river,  and  afterwards,  by  another  aqueduct, 
one  thousand  one  hundred  and  eighty-eight  feet  in  length, 
and  at  last  reaches  the  city  of  Albany. 

Albany  is  the  capital  of  the  State  of  New  York,  and  con- 
tains a  population  of  about  thirty  thousand.  It  is  situate 
on  the  west,  or  right,  bank  of  the  Hudson,  at  the  head  of 
the  natural  navigation  of  the  river  ;  but  some  improve- 
ments have  been  made,  which  enable  vessels  of  smaP 
burden  to  ascend  as  far  as  Waterford,  thirteen  miles  above 
Albany.  One  of  these  improvements  has  been  efi^ected  by 
the  erection  of  a  dam  across  the  Hudson,  eleven  hundred 
feet  in  length,  and  nine  feet  in  height,  at  a  cost  of  up- 
wards of  ^£18,000.  The  lock,  connected  with  this  dam, 
measures  one  hundred  and  fourteen  feet  in  length,  and 
thirty  feet  in  breadth.  Albany,  however,  may  be  said 
to  monopolize  the  trade  of  the  river,  and,  in  addition  to 
the  interest  it  possesses  as  a  place  of  great  commerce,  it 
is  important  from  its  position  at  the  outlet  of  the  Erie 
canal,  and  as  the  seat  of  a  large  basin,  or  depot,  for  the 


310  APPENDIX. 

accommodation  of  the  boats  navigating  it.  This  basin, 
which  has  an  area  of  thirty-two  acres,  is  formed  by  an 
enormous  mound,  placed  lengthwise  with  the  stream  of 
the  river  Hudson,  and  enclosing  a  part  of  its  surface. 
The  mound  is  composed,  chiefly,  of  earth,  and  is  four 
thousand  three  hundred  feet  in  length,  and  eighty  feet  m 
breadth,  and,  being  completely  covered  with  large  warp- 
houses,  it  now  forms  a  part  of  the  city  of  Albany,  w^itn 
which  it  is  connected  by  means  of  numerous  drawbridges 
The  place  has,  in  consequence,  very  much  the  same  ap- 
pearance as  many  of  the  Dutch  towns.  The  lower  ex- 
tremity of  the  mound  is  unconnected  with  the  shore,  ? 
large  passage  being  left  for  the  ingress  and  egress  of  ves- 
sels ;  but  its  upper  end  is  separated  from  the  bank  oi 
the  river,  by  a  smaller  opening,  which  is  closed,  when 
necessary,  to  prevent  ice  from  injuring  the  craft  lying  in 
the  basin.  A  stream  of  water  is  generally  allowed  to 
enter  at  the  upper  end,  which,  flowing  through  the  basin, 
acts  as  a  scour,  and  prevents  it  from  silting  up.  The 
mound  is  surrounded  by  a  wooden  wharf,  like  those  of 
New  York  and  Boston,  at  which  vessels  discharge  and 
load  their  cargoes.  This  admirable  basin  forms  a  part 
of  the  Erie  canal  works,  and  cost  about  £26,000. 

According  to  the  Report  of  the  Canal  Commissioners, 
dated  March,  1837,  the  number  of  boats,  registered  in 
the  Comptroller's  office,  as  navigating  the  Erie  canal  and 
its  branches,  was. 

In  1834,         .         2,585 

"   1835,         .         2,914     Increase,  329 

"   1836,         .         3,167  "         253 

The  total  number  of  clearances,  or  trips  made  during 
the  same  years,  was, 

In  1834,  .  64,794 
*'  1835,  .  69,767 
"  1836,    .    67,270 

The  average  number  of  lockages,  per  day,  at  each 
lock  was. 

In  1834,    .    95i 
"  1835,    .   112 
"  1836.    .   lis 


CANALS  IN  THE  UNITED   STATES.  311 

The  whole  tonnage,  transported  on  the  canal,  during 
the  year  1836,  was  1,310,807  tons,  the  value  of  which 
amounted  to  §67,643,343,  or  £13,526,868.  The  pro- 
portion between  the  weight  of  freight,  conveyed  from 
the  Hudson  to  the  interior  of  the  country,  and  that  con- 
veyed from  the  interior  of  the  country  to  the  Hudson, 
was  in  the  ratio  of  one  to  five.  The  tolls,  collected  in 
1836,  for  the  conveyance  of  goods  and  passengers, 
amounted  to  £322,867.  The  rates  of  charge,  accord- 
ing to  which  the  tolls  are  collected,  are  annually  changed, 
to  suit  the  circumstances  of  the  trade,  and  are  not  the 
same  throughout  the  whole  line  of  the  canal,  which  ren- 
ders it  difficult  to  give  a  view  of  them.  In  1836,  the 
passage-money  from  Albany  to  Buffalo,  in  the  packet- 
boat,  w^as  £S  35.,  being  at  the  rate  of  nearly  2d.  per  mile  ; 
and  in  a  line-boat,  which  is  an  inferior  conveyance,  £1 
1 8s.,  being  at  the  rate  of  one  penny  and  two  tenths  per 
mile.  The  expenditure  for  keeping  the  canal  and  iis 
branches  in  repair,  during  1836,  w'as  §410,236,  or  about 
£82,047  ;  which,  taking  the  whole  length  at  five  hundred 
and  forty-three  miles,  gives  an  average  of  £151  per  mile. 
The  average  cost  of  repairs,  for  the  six  preceding  years, 
amounted  to  £136  per  mile. 

Before  leaving  the  subject  of  canals,  I  must  not  omit 
to  mention  the  Morris  canal,  in  the  State  of  New  Jer- 
sey. This  canal  leads  from  Jersey,  on  the  Hudson,  to 
Easton,  on  the  Delaware,  and  connects  these  two  rivers. 
The  breadth,  at  the  water  hne,  is  thirty-two,  and  at  the 
bottom,  sixteen,  feet,  and  the  depth  is  four  feet.  It  is 
one  hundred  and  one  miles  in  length,  and  is  said  to  have 
cost  about  £600,000.  It  is  peculiar,  as  being  the  only 
canal  in  America,  in  which  the  boats  are  moved  from  dif 
ferent  levels  by  means  of  inclined  planes,  instead  of  locks  , 
a  construction,  which  was  first  introduced  on  the  Duke 
of  Bridgewater's  canal,  in  England.  The  whole  rise  and 
fall,  on  the  Morris  canal,  is  one  thousand  five  hundred 
and  fifly-seven  feet,  of  w^hich  two  hundred  and  twenty- 
three  feet  are  overcome  by  locks,  and  the  remaining  one 
thousand  three  hundred  and  thirty-four  feet,  by  means  of 
twenty- three  inclined  planes,  having  an  average  lift  of 


312  APPENDIX. 

fifty-eight  feet  each.  The  boats,  which  navigate  this 
canal,  are  eight  and  one  half  feet  in  breadth  of  beam, 
from  sixty  to  eighty  feet  in  length,  and  from  twenty-five 
to  thirty  tons  burden.  The  greatest  weight  ever  drawn 
up  the  planes  is  about  fifty  tons.  The  boat-car  used  on 
this  canal,  consists  of  a  strongly  made  wooden  crib,  or 
cradle,  on  which  the  boat  rests,  supported  on  two  iron 
wagons  running  on  four  wheels.  When  the  car  is  wholly 
supported  on  the  incHned  plane,  or  is  resting  on  a  level, 
the  four  axles  of  the  wagons  are  all  in  the  same  plane  ; 
but  when  one  of  the  w^agons  rests  on  the  inclined  plane, 
and  the  other  on  the  level  surface,  their  axles  no  longer 
remain  in  the  same  plane,  and  their  change  of  position 
produces  a  tendency  to  rack  the  cradle,  and  the  boat 
which  it  supports  ;  but  this  has  been  guarded  against,  in 
the  construction  of  the  boat-cars  on  the  Morris  canal,  by 
introducing  two  axles,  on  which  the  whole  w^eight  of  the 
crib  and  boat  are  supported,  and  on  which  the  wagons 
turn,  as  a  centre.  The  cars  run  on  plate-rails,  laid  on 
the  inclined  planes,  and  are  raised  and  lowered  by  means 
of  machinery  driven  by  water-wheels.  The  rail-way,  on 
which  the  car  runs,  extends  for  a  short  distance  from  the 
lower  extremity  of  the  plane,  along  the  bottom  of  the 
canal.  When  a  boat  is  to  be  raised,  the  car  is  lowered 
into  the  water,  and  the  boat  being  floated  over  it,  is  made 
fast  to  the  part  of  the  framework  which  projects  above  the 
gunwale.  The  machinery  is  then  put  in  motion  ;  and  the 
car,  bearing  the  boat,  is  drawn  by  a  chain  to  the  top  of 
the  inclined  plane,  at  which  there  is  a  lock  for  its  recep- 
tion. The  lock  is  furnished  with  gates,  at  both  extremi- 
ties ;  after  the  car  has  entered  it,  the  gates  next  the  top 
of  the  inclined  plane  are  closed,  and,  those  next  the  canal 
being  opened,  the  w^ater  flows  in  and  floats  the  boat  off 
the  car,  when  she  proceeds  on  her  way.  Her  place  is 
supplied  by  a  boat  travelling  in  the  opposite  direction, 
which  enters  the  lock,  and  the  gates  next  the  canal  being 
closed,  and  the  water  run  off,  she  grounds  on  the  car. 
The  gates  next  the  plane  are  then  opened,  the  car  is  gen- 
tly lowered  to  the  bottom,  when  it  enters  the  w^ater,  and 
the  boat  is  again  floated.     The  principal  objection,  urged 


CANALS  IN  THE  UNITED   STATES.    .  313 

against  the  use  of  inclined  planes,  in  canal  navigation,  for 
moving  boats  from  different  levels,  is  founded  on  the  in- 
jury which  the  boats  are  apt  to  sustain  in  supporting  great 
weights,  while  resting  on  the  cradle,  during  its  passage 
over  the  planes.  It  can  hardly  be  supposed  that  a  shm- 
ly-built  canal-boat,  measuring  from  sixty  to  eighty  feet  in 
length,  and  loaded  with  a  weight  of  twenty  or  thirty  tons, 
can  be  grounded,  even  on  a  smooth  surface,  without  strain- 
ing and  injuring  her  timbers  ;  a  circumstance  which  is  a 
decided  objection  to  this  mode  of  construction,  and  has 
operated  powerfully  in  preventing  its  introduction  in  many 
situations,  both  in  this  country  and  in  America.  But, 
notwithstanding  this  objection,  the  twenty-three  inclined 
planes  on  the  Morris  canal  are  in  full  operation,  and  act 
exceedingly  well.  No  pains  have  been  spared  to  render 
the  machinery  connected  with  them  as  perfect  as  possible, 
and  the  greatest  credit  is  due  to  the  engineer  for  the  suc- 
cess which  has  hitherto  attended  the  operation. — Steven- 
son^s  '  Sketches  of  Civil  Engineering  in  Mrth  America.^ 

II.  27  XII. 


314 


APPENDIX 


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318  APPENDIX. 


V. — Rail-ways  in  the  United  States. 

Within  a  very  (ew  years,  a  wonderful  change  has  been 
effected  in  land-communication  throughout  Great  Brit- 
ain and  America,  where  rail-ways  have  been  more  ex- 
tensively and  successfully  introduced  than  in  any  other 
parts  of  the  world.  As  early  as  the  sixteenth  century, 
wooden  tram-roads  were  used  in  the  neighborhood  of 
many  of  the  collieries  of  Great  Britain.  In  the  year 
1767,  cast-iron  rails  were  introduced  at  Colebrookdale,  in* 
Shropshire.  In  IS  11,  malleable  iron  rails  were,  for  the 
first  time,  used  in  Cumberland,  and  the  locomotive  en- 
gine, on  an  improved  construction,  was  successfully  in- 
troduced on  the  Liverpool  and  Manchester  line,  in  1830. 
Little  progress  has  hitherto  been  made  in  the  formation 
of  rail- ways  on  the  Continent  of  Europe.  A  small  one 
has  been  in  existence,  for  some  time,  in  the  neighborhood 
of  Lyons  ;  but  the  only  rail-road,  constructed  in  France, 
for  the  conveyance  of  passengers  by  locomotive  power, 
is  that  from  Paris  to  St.  Germains,  which  was  opened 
only  in  1837.  In  Bohemia,  the  ChevaHer  Gerstner, 
about  eight  years  ago,  constructed  a  rail-way  of  eighty 
miles  in  length,  leading  from  the  river  Muldau  to  the  Dan- 
ube. In  Belgium,  the  rail-way  from  Antwerp  to  Ghent 
has  been  in  use  for  some  time  ;  and  some  lines  are  at  pres- 
ent being  constructed  in  Holland  and  Russia.  But  the 
purpose  of  the  present  article  is  to  describe  the  state  of 
this  wonderful  improvement  in  communication,  in  the 
United  States. 

The  Quincy  rail-road,  in  Massachusetts,  .was  the  first 
constructed  in  America.  It  was  intended  for  the  con- 
veyance of  stone  from  the  Quincy  granite-quarries  to  a 
shipping  port,  on  the  river  Neponset,  a  distance  of  about 
four  miles.  At  the  end  of  this  article  is  given  a  tabular 
list  of  the  principal  rail-roads  which  are  already  finished, 
and  also  of  those  that  have  been  begun  in  the  United 
States,  which  show  the  rapid  increase  of  these  works 
since  1827,  the  date  at  which  the  Quincy  rail-road  was 
completed.  From  these  tables  it  appears  that,  in  1840, 
there  were  no  fewer  than  seventy-one  rail-ways  completed. 


RAIL-WAYS   IN  THE    UNITEL    STATES.  319 

and  in  full  operation,  whose  aggregate  length  amounts  to 
about  twenty-three  hundred  miles  ;  and  also,  that  twenty- 
three  rail-ways  were  then  in  progress,  which,  when  com- 
pleted, will  amount  to  about  twenty- eight  hundred  miles. 
In  addition  to  this,  upwards  of  one  hundred  and  fifty  rail- 
way companies  have  been  incorporated ;  and  the  works 
of  many  of  them  will,  in  all  probability,  be  very  soon 
commenced. 

The  Boston  and  Lowell  rail-way,  in  Massachusetts,  is 
twenty-six  miles  in  length,  and  is  laid  with  a  double  line 
of  rails.  The  breadth  between  the  rails,  which  is  four 
feet  eight  and  a  half  inches,  is  the  s.ame  in  all  the  Ameri- 
can rail-roads,  and  the  breadth  between  the  tracks  is  six 
feet. 

The  supporters  are  granite  blocks,  six  feet  in  length, 
and  about  eighteen  inches  square.  These  are  placed 
transversely,  at  distances  of  three  feet  apart,  from  centre 
to  centre,  each  block  giving  support  to  l30th  of  the  rails. 
This  construction  was  first  introduced  in  the  Dublin  and 
Kingstown  rail-way,  in  Ireland,  but  was  found  to  pro- 
duce so  rigid  a  road,  that  great  difiiculty  was  experienced 
in  securing  the  fixtures  of  the  chairs.  From  the  difficulty, 
also,  of  procuring  a  solid  bed  for  stones  of  so  great  di- 
mensions, most  of  them,  after  being  subjected  for  a  short 
time  to  the  traffic  of  the  rail-way,  were  found  to  be  split. 

Another  construction  has  been  tried  on  this  line,  con- 
sisting of  longitudinal  trenches,  two  feet  six  inches 
square,  and  four  feet  eight  and  a  half  inches  apart,  from 
centre  to  centre,  formed  in  the  ground,  and  filled  with 
broken  stone,  hard  punned  down  with  a  wooden  beater, 
as  a  foundation  for  the  stone  blocks  on  which  the  rails 
rest.  These  blocks  measure  two  feet  square,  and  a  foot 
in  thickness,  and  a  transverse  sleeper  of  wood,  two  feet 
eight  inches  and  a  half  in  length,  one  foot  in  breadth,  and 
eight  inches  in  th'ckness,  is  placed  between  the  blocks, 
to  prevent  them  from  moving. 

The  plan  of  resting  the  rail-way  on  a  foundation  of  brok 
en  stone  was  adopted,  in  the  expectation  that  it  might  be 
sunk  to  a  sufficient  depth  below  the  surface  of  the  ground, 
to  prevent  the   frost  from  affecting   it ;  bat   subsequent 


320  APPENDIX. 

experience  has  shown  that  many  of  those  rail-ways,  whose 
construction  was  more  superficial,  have  resisted  the  ef- 
fects of  frost  much  better. 

The  New  York  and  Patterson  rail-way  is  sixteen  and 
a  half  miles  in  length,  and  extends  along  a  marshy  tract 
of  ground.  The  foundation  of  the  road  consists  of  a 
line  of  pits  under  each  rail,  eighteen  inches  square,. and 
three  feet  in  depth.  They  are  placed  three  feet  apart, 
from  centre  to  centre,  and  filled  with  broken  stones.  On 
this  foundation,  transverse  wooden  sleepers,  measuring 
eight  inches  square,  and  seven  feet  in  length,  are  firmly 
bedded,  on  w^hich  rest  the  longitudinal  sleepers,  measur- 
ing eight  inches  by  six.  To  these,  plate-rails  of  mallea- 
ble iron,  two  and  a  half  inches  wide,  and  half  an  inch 
thick,  weighing  about  thirteen  pounds  per  lineal  yard,  are 
fixed  by  iron  spikes. 

In  the  Saratoga  and  Schenectady  rail-way,  the  paral- 
lel trenches  are  eighteen  inches  square,  and  four  feet 
eight  and  a  half  inches  apart,  from  centre  to  centre.  They 
extend  throughout  the  whole  line  of  the  rail-way,  and  are 
firmly  punned  full  of  broken  stones.  Longitudinal  sleep- 
ers of  wood,  measuring  eight  by  five  inches,  are  placed 
on  these  trenches,  which  support  the  transverse  wooden 
sleepers,  measuring  six  inches  square,  and  placed  three 
feet  apart,  from  centre  to  centre.  Longitudinal  runners, 
measuring  six  inches  square,  are  firmly  spiked  to  the 
transverse  sleepers,  and  the  whole  is  surmounted  by  a 
plate-rail,  half  an  inch  thick,  and  two  and  a  half  inches 
wide,  weighing  about  thirteen  pounds  per  lineal  yard. 

The  Newcastle  and  Frenchtown  rail- way,  which  is 
sixteen  miles  in  length,  and  forms  part  of  the  route  from 
Philadelphia  to  Baltimore,  is  constructed  in  the  same  way 
as  that  between  Schenectady  and  Saratoga,  excepting 
that  the  plate-rail  is  two  and  a  half  inches  broad,  and  five 
eighths  of  an  inch  thick,  and  weighs  nearly  sixteen  pounds 
per  lineal  yard.  The  Baltimore  and  Washington  rail- 
way is  also  constructed  in  the  same  manner,  as  regards  the 
foundation  and  arrangement  of  the  timbers  ;  but  edge-rails 
are  employed  on  that  line,  three  and  a  half  inches  in 
breadth  at  the  base,  and  two  inches  in  height. 


RAIL-WAYS   IN  THE  UNITED   STATES.  321 

Several  experiments  have  been  made  on  the  Columbia 
rail-road,  in  Pennsylvania,  which  is  eighty-two  miles  in 
length,  and  is  under  the  management  of  the  State.  Part 
of  the  road  is  constructed  with  trenches  measuring  two 
feet  six  inches  in  breadth,  and  two  feet  in  depth,  excava 
ted  in  the  ground,  and  filled  with  broken  stone.  In  these, 
the  stone  blocks,  two  feet  square,  and  a  foot  in  thickness, 
are  imbedded,  at  distances  of  three  feet  apart,  to  which 
the  chairs  and  rails  are  spiked,  in  the  ordinary  manner. 
The  rails  on  each  side  of  the  track  are  connected  togeth- 
er by  an  iron  bar.  This  attachment  is  rendered  absolute- 
ly necessary,  on  many  parts  of  the  Columbia  rail-road, 
by  the  sharpness  of  the  curves,  which,  at  the  time  when 
the  work  was  laid  out,  were  not  considered  so  prejudicial 
on  a  rail-way,  as  experience  has  shown  them  to  be. 

Another  plan  tried  on  this  road  has  a  continuous  line  ot 
stone  curb,  one  foot  square,  resting  on  a  stratum  of  broken 
stone,  instead  of  the  isolated  stone  blocks.  A  plate-rail, 
half  an  inch  thick,  and  two  and  a  half  inches  broad,  is 
spiked  down  to  treenails,  of  oak  or  locust  wood,  driven 
into  jumper-holes  bored  in  the  stone  curb. 

The  Boston  and  Providence  rail-way  is  forty-one  miles 
in  length.  Pits,  measuring  eighteen  inches  square,  and 
one  foot  in  depth,  are  excavated  under  each  hne  of  rail, 
at  intervals  of  four  feet  apart.  They  are  filled  with  broken 
stone,  and  form  a  foundation  for  the  transverse  wooden 
sleepers,  measuring  eight  inches  square,  on  which  the 
chairs  and  rails  are  fixed  in  the  usual  manner. 

One  of  the  tracks,  in  very  general  use  in  America,  is 
met  with  on  the  Philadelphia  and  Norristown.  the  New 
York  and  Haerlemand  the  Buffalo  and  Niagara  rail-roads  ; 
and  has  been  mtroduced  on  many  others.  It  consists 
of  two  lines  of  longitudinal  wooden  runners,  measuring 
one  foot  in  breadth,  and  from  three  to  four  inches  in 
thickness,  bedded  on  broken  stone,  or  gravel.  On  these 
^runners,  transverse  sleepers  are  placed,  formed  of  round 
timber,  with  the  bark  left  on,  measuring  about  six  inches 
in  diameter,  and  squared  at  the  ends,  to  give  them  a  prop- 
er rest.  Longitudinal  sleepers,  for  supporting  the  rails, 
are  notched  into  the  transverse  sleepers.     The  rail  is  flat. 


322  APPENDIX. 

made  of  wrought-iron,  and  varies  in  weight  from  ten  to  fif- 
teen pounds  per  lineal  yard.  It  is  fixed  down  to  the  sleep- 
ers, at  every  fifteen  or  eighteen  inches,  by  spikes  four  or 
five  inches  in  length,  the  heads  of  which  are  countersunk 
in  the  rail. 

The  rails  used  on  the  Camden  and  Amboy  rail-way, 
w^hich  is  sixty-one  miles  in  length,  are  parallel  edge-rails, 
and  are  spiked  to  transverse  sleepers  of  wood,  and,  in 
some  places,  to  w^ood  treenails  driven  into  stone  blocks. 
Their  breadth  is  three  and  a  half  inches  at  the  base,  and 
two  and  a  half  at  the  top,  and  their  height  is  four  inches. 
They  are  formed  in  lengths  of  fifteen  feet,  and  secured  at 
the  joints  by  an  iron  plate  on  each  side,  with  two  screw- 
bolts  passing  through  the  plates  and  rails.  On  the  Phila- 
delphia and  Reading  rail-road,  rails  of  the  same  form 
have  been  adopted. 

On  several  of  the  rail-roads,  with  a  view  to  counteract 
the  effects  of  frost,  round  piles  of  timber,  about  twelve 
inches  in  diameter,  are  driven  into  the  ground  as  far  as 
they  will  go,  at  the  distance  of  three  feet  apart,  from  cen- 
tre to  centre.  The  tops  are  cross-cut,  and  the  rails  are 
spiked  to  them  in  the  same  way  as  in  the  Camden  and 
Amboy  Rail-way.  The  heads  of  the  piles  are  furnished 
with  an  iron  strap,  to  prevent  them  from  splitting  ;  and 
the  rails  are  connected  together,  at  every  five  feet,  by  an 
iron  bar. 

The  Brooklyn  and  Jamaica  rail-road  is  exceedingly 
smooth,  and  is  said  to  resist  the  effects  of  frost  very  suc- 
cessfully. It  consists  of  transverse  sleepers,  measuring 
eight  by  six  inches,  supported  on  slabs  of  pavement,  two 
feet  square,  and  six  inches  thicli.  The  wooden  runner 
;s  spiked  on  the  inside  of  the  chairs,  to  render  tnem  firm 
This  rail  rests  on  the  cheeks^  or  sides,  of  tne  cnair,  ana 
not  on  the  bottom,  as  is  generally  the  case. 

The  rail-road  between  Charleston  and  Augusta,  and 
many  others  in  the  southern  States,  where  there  is  a  scar- 
city of  materials  for  forming  embankments,  are  carried 
over  low-lying  tracts  of  marshy  ground,  elevated  on  struc- 
tures of  wooden  truss-work.  The  framing  is  nsed  in  sit- 
uations where  the  level  of  the  rails  does  not  require  to  be 


RAIL-WAYS   IN   THE   UNITED   STATES.  o2o 

raised  more  than  ten  or  twelve  feet  above  the  surface  of 
the  ground.  Piles, from  ten  to  fifteen  inches  in  diameter, 
are  driven  into  the  ground  by  a  piling  engine,  and,  in 
places  where  the  soil  is  soft,  their  extremities  are  not 
pointed,  but  are  left  square,  which  makes  them  less  liable 
to  sink  under  the  pressure  of  the  carriages.  The  struts 
are  attached  to  the  tops  of  the  piles,  and  are  also  fixed 
i*>  dwarf  piles  driven  into,  the  ground.  Their  effect  is  to 
prevent  lateral  motion.  It  is  evident,  however,  that  these 
structures  are  by  no  means  suitable  or  safe,  for  bearing 
the  weight  of  locomotive  engines  or  carriages  ;  and,  as 
may  naturally  be  expected,  very  serious  accidents  have 
ocjasionally  occurred  on  them.  They  are,  besides,  gen- 
erally left  quite  exposed,  and,  in  some  situations,  when 
they  are  even  so  much  as  twenty  feet  high,  no  room 
is  left  for  pedestrians,  who,  if  overtaken  by  the  en- 
gine, can  save  themselves  only  by  making  a  leap  to  the 
ground. 

These  varieties  of  construction  were  all  in  use  in  the 
United  States  in  1837  ;  but  the  American  engineers  had 
not,  at  that  time,  come  to  any  definite  conclusion,  as  to 
which  of  them  constituted  the  best  rail-way.  It  seemed 
to  be  generally  admitted,  however,  that  the  wooden  struc- 
tures were,  in  most  situations,  more  economical  than  those 
formed  of  stone,  and  were  also  less  liable  to  be  affected 
by  the  frost.  Structures  of  wood  also  possess  a  great 
advantage  over  those  of  stone,  from  the  much  greater  ease 
with  which  the  rails  supported  by  them  are  kept  in  repair. 
Wooden  rail-roads  are  more  elastic,  and  bend  under  great 
weights,  while  the  rigid  ana  unyielding  nature  of  the  rail 
roads  laid  on  stone  blocks  causes  the  impulses,  producec 
oy  the  rapia  motion  of  locomotive  carriages,  or  heavily 
loaded  wagons,  over  the  surface,  to  be  much  more  severe- 
ly felt,  both  by  the  machinery  of  the  engine,  and  by  the 
rails  themselves.  Experience,  both  in  this  country  and 
in  America,  has  shown  the  truth  of  these  remarks.  On 
the  Liverpool  and  Manchester  rail-way,  for  example,  on 
which  a  large  sum  is  annually  expended  in  keeping  the  rails 
in  order,  the  part  of  the  road  which  requires  least  repair 
!s  that  extending  over  Chat  Moss,  where  the  rails  are  laid 


324  APPENDIX. 

on  wooden  sleepers,  and  the  weight  of  passing  trains  ol 
loaded  wagons  produces  a  sensible  undulation  in  the  sur- 
face of  the  rail-way,  which  at  this  place  actually  floats  on 
the  moss.  These  considerations  are  worthy  of  attention  ; 
and,  since  the  introduction  of  Kyan's  patent  anti-dry-rot 
preparation,  wood  is  beginning  to  be  more  generally  em- 
[)loyed  for  the  construction  of  rail-ways  in  this  country. 
The  rails  of  the  Dublin  and  Kingstown  road  are  now  laid 
on  wood,  and  it  has  also  been  extensively  employed  on  the 
Great  Western  rail-way,  now  in  progress. 

The  rails  used  in  the  United  States  are  of  British  man- 
ufacture. They  are  often  taken  to  iVmerica  as  ballast  ; 
and  the  Government  of  the  United  States  having  remov- 
ed the  duty  from  iron  imported  for  the  purpose  of  forming 
rail-ways,  the  rails  are  laid  down  on  the  quays  of  New  York 
nearly  at  the  same  cost,  as  in  any  of  the  ports  of  Great 
Britain.  Those  of  the  Brooklyn  and  Jamaica  road,  which 
are  in  lengths  of  fifteen  feet,  and  weigh  thirty-nine  pounds 
per  lineal  yard,  are  of  British  manufacture,  and  cost  at  New 
York,  when  they  were  landed,  in  1836,  £S  per  ton ;  the 
cast-iron  chairs,  which  are  also  of  British  manufacture, 
weigh  about  fifteen  pounds  each,  and  cost  <£9  per  ton. 
There  is  a  great  abundance  of  iron  ore  in  America,  and 
some  of  the  veins  in  the  neighborhood  of  Pittsburg  are  at 
present  pretty  extensively  worked  ;  but  the  Americans 
know  that  it  would  be  bad  economy  to  attempt  to  manufac- 
ture rails,  so  long  as  those  made  at  Merthyr  Tydvil  Iron- 
works, in  Wales,  can  be  laid  down  at  their  sea-ports  at 
the  present  small  cost. 

The  stone  blocks,  in  use  on  some  of  the  rail-wavs.  are 
inade  of  granite,  which  is  found  in  many  parts  of  the 
United  States.  Yellow  pine  is  generally  employed  for 
tne  longitudinal  sleepers,  and  cedar,  locust,  or  white-oaK, 
for  the  transverse  sleepers  on  which  the  rails  rest.  Cedar, 
however,  if  it  can  be  obtained,  is  generally  preferred  for 
the  transverse  sleepers,  because  it  is  not  liable  to  be  split 
by  the  heat  of  the  sun,  and  is  less  affected  than  perhaps 
any  other  timber,  by  dampness  and  exposure  to  the  at- 
mosphere. The  cedar  sleepers  used  on  the  Brooklyn 
and  Jamaica  rail-way,  measuring  six  inches  by  five,  and 


RAIL-WAYS   IN  THE  UNITED   STATES.  325 

seven  feet  in  length,  notched,  and  in  readiness  to  receive 
the  rails,  cost  ^s.  S^d.  each,  laid  down  at  Brooklyn.  It 
is  a  costly  timber,  and  is  not  very  plentiful  in  the  United 
States.  It  has  also  risen  greatly  in  value,  since  the  intro- 
duction of  rail-ways,  for  the  construction  of  which  it  is 
peculiarly  applicable.  For  all  treenails,  locust-wood  is 
universally  employed. 

The  American  rail-roads  are  much  more  cheaply  con- 
structed than  those  in  England,  which  is  owing  chiefly  to 
three  causes ;  firsts  they  are  exempted  from  the  heavy 
expenses  often  incurred  in  the  construction  of  English  rail- 
ways, by  the  purchase  of  land,  and  compensation  for  dam- 
ages ;  second,  the  works  are  not  executed  in  so  substantial 
and  costly  a  style  ;  and,  third,  wood,  which  is  the  prin- 
cipal material  used  in  their  construction,  is  got  at  a  very 
small  cost.  The  first  six  miles  of  the  Baltimore  and 
Ohio  rail-road,  which  is  formed  "in  an  expensive  man- 
ner, on  a  very  difficult  route,"  has  cost,  on  an  average, 
about  £12,000  per  mile.  The  rail-roads  in  Pennsylva- 
nia cost  about  £5000  per  mile  ;  the  Albany  and  "Sche- 
nectady rail-road,  upwards  of  £6000  per  mile  ;  the  Sche- 
nectady and  Saratoga  rail- way,  £1800  per  mile  ;  and  the 
Charleston  and  Augusta  rail-road,  about  the  same.*  Mr. 
Moncure  Robinson,  in  a  report  relative  to  the  Philipsburg 
and  Juniata  rail-road,  states,  that  the  first  ten  miles  of 
the  Danville  and  Pottsville  rail-road,  formed  for  a  double 
track,  but  on  which  a  single  track  only  was  laid,  cost,  on 
an  average,  £4400  per  mile,  and  that  the  Honesdale  and 
Carbondale  rail-road,  sixteen  and  one  third  miles  in  length, 
laid  with  a  single  track,  and  executed  for  a  considerable 
Dortion  of  its  length  on  truss-work,  is  understooa,  wiin 
niacnmery,  to  have  averaged  £3600  per  mile.  The 
average  cost  of  these  rail-ways,  constructed  m  diflx;renk 
parts  of  the  United  States,  is  £4942  per  mile. 

This  contrasts,  strongly,  with  the  cost  of  the  rail-ways 
constructed  in  Great  Britian.  The  Liverpool  and  Man- 
chester rail-way  cost  £30,000  per  mile ;  the  Dublin  and 

*  Facts  and  suggestions  relative  to  the  New  York  and  Albany  rail 
way.     New  York,  1833. 

II.  28  XII. 


326 


APPENDIX. 


Kingstown,  £40,000  ;  and  the  rail- way  between  Liverpod 
and  London  is  expected  to  cost  upwards  of  £25,000. 

The  following  extract,  embodying  an  estimate  from  Mr. 
Robinson's  Report,  will  give  some  idea  of  the  cheapness 
with  which  many  of  the  American  works  are  construc- 
ted : — 

"  The  following  plan,"  says  Mr.  Robinson,  '-is  pro- 
posed for  the  superstructure  of  the  Philipsburg  and  Juni- 
ata rail-road. 

"  Sills  of  white  or  post  oak,  seven  feet  ten  inches  long, 
and  twelve  inches  in  diameter,  flattened  to  a  width  of 
nine  inches,  are  to  be  laid  across  the  road,  at  a  distance 
of  five  feet  apart,  from  centre  to  centre.  In  notches 
formed  in  these  sills,  rails  of  white-oak  or  heart-pine,  tive 
inches  wide  by  nine  inches  in  depth,  are  to  be  secured, 
four  feet  seven  inches  apart,  measured  within  the  rails. 
On  the  inner  edges  of  these  rails,  plates  of  rolled  iron, 
two  inches  wide  by  half  an  inch  thick,  resting  at  their 
points  of  junction  on  plates  of  sheet  iron,  one  twelfth  of 
an  inch  thick  and  four  and  a  half  inches  long,  are  to  be 
spiked,  with  five-inch  wrought-iron  spikes.  The  inner 
edges  of  the  wooden  rails  to  be  trimmed  slightly  level- 
ling, but  flush  at  the  point  of  contact  with  the  iron  rail, 
and  to  be  adzed  down,  outside  the  iron,  to  pass  off  rain- 
water. 

"  Such  a  superstructure,  as  that  above  described,  would 
be  entirely  adequate  to  the  use  of  locomotive  engines  of 
from  fifteen  to  twenty  horses' power,  constructed  without 
surplus  weight,  or  similar  to  those  now  in  use  on  the  little 
Schuylkill  rail-road  in  this  State.  (Pennsylvania,)  or  tne 
Petersburg  rail-road  m  Virgmia  :  and  it  will  be  observea 
mat  only  tlie  sills,  which  constitute  but  a  very  slight  item 
in  its  cost,  are  much  exposed  to  the  action  of  those  causes 
which  induce  decay  in  timber.  It  is  particularly  recom- 
mended for  the  Philipsburg  and  Juniata  rail-road,  by  the 
great  abundance  of  good  materials,  along  the  line  of  the 
improvement,  for  its  construction,  and  the  consequent 
economy  wuth  which  it  may  be  made. 

"  The  following  may  be  deemed  an  average  estimate 
of  the  cost  of  a  mile  of  superstructure,  as  above  described. 


RAIL-WAYS   IN  THE   UNITED   STATES.  327 

1056  trenches,  8  feet  long,  12  inches  wide,  and  14  inches  Uolls. 

deep,  filled  with  broken  stone,  at  25  cents  each,         .  264 
Same  number  of  sills,  hewn,  notched,  and  imbedded,  at 

50  cents  each,  .......  528 

10,912   lineal   feet  of  rails,  (allowing   33^   per  cent,  for 

waste,)  at  4  cents  per  lineal  foot,  delivered,         .      .  436.43 

2112  keys,  at  2^  cents  each, 52.80 

10,560  lineal  feet  of  plate  rails,  2  inches  by  ^  inch,  weight 

3^  lb.  per  foot,  ISy'^^g-  tons,  delivered  at  50  dollars 

(£10)  per  ton, 785  50 

1509  lbs.  of  5-inch  spikes,  at  9  cents  per  pound,        .         .  135  81 
Sheet  iron  under  ends  of  rails,           .....  30.21 

Placing  and  dressing  wood,  and  spiking  down  iron  rails,  280 

Filling  between  sills  with  stone,  or  horse-path,  .         .  180 

2692  dollars,  or  about  £540.  ,  2692.80 

It  was  found  rather  difficult  to  obtain  much  satisfactory 
information  regarding  the  expense  of  upholding  the  Amer- 
ican rail-ways.  It  is  stated  in  a  report  made  by  the  Di- 
rectors of  the  Boston  and  Worcester  rail-road,  that  Mr. 
Fessenden,  their  engineer,  estimates  the  annual  expendi- 
ture for  repairing  the  road,  carriages,  and  engines,  and  pro- 
viding fuel  and  necessary  attendance  for  forty-three  and  a 
half  miles  of  rail-way,  at  £6829  per  annum,  which  is  at  the 
rate  of  £157  per  mile.  The  expense  of  the  repairs  on  the 
Utica  and  Schenectady  rail-road,  which  is  about  seventy- 
seven  miles  in  length,  amounts  to  £23,000  per  annum,  be- 
ing at  the  rate  of  about  £363  per  mile.  These  sums  for 
keeping  rail-roads  in  repair  are  exceedingly  small,  compar- 
ed with  the  amount  expended  in  this  country  for  the  same 
purpose.  On  the  Liverpool  and  Manchester  rail-way,  for 
example,  the  expense  annually  incurred,  in  keeping  the 
engines  in  a  working  state,  and  the  rail-wav  in  repair. 
amounts  to  upwards  of  £30,000,  or  £1000  per  miJt^ 
This  difference  in  the  cost  arises,  m  a  a^reat  measure,  iron, 
tne  comparatively  slow  speed  at  which  the  engines  work- 
ing on  the  American  rail-ways  are  propelled,  which,  in  the 
course  of  my  own  observation,  never  exceeded  the  aver- 
age rate  of  6fteen  miles  per  hour.  On  the  State  rail-ways, 
and  also  on  many  of  those  under  the  management  of  in- 
corporated companies,  fifteen  miles  an  hour  is  the  rate  of 
travelling  fixed  by  the  administration  of  the  rail-way,  and 
•his  speed  is  seldom  exceeded. 


328  APPENDIX. 

On  some  of  the  American  rail-ways,  where  the  line  is 
short,  or  the  traffic  small,  horse  power  is  employed  ;  but 
locomotive  engines  for  transporting  goods  and  passen- 
gers, are  in  much  more  general  use.  In  New  Ycrk, 
Brooklyn,  Philadelphia,  Baltimore,  and  other  places, 
which  have  lines  of  rail-way  leading  from  them,  the  depot, 
or  station  for  the  locomotive  engines,  is  generally  placed 
at  the  outskirts,  but  the  rails  are  continued  through  the 
streets,  to  the  heart  of  the  town,  and  the  carriages  are 
dragged  over  this  part  of  the  line  by  horses,  to  avoid  the 
inconvenience  and  danger,  attending  the  passage  of  loco- 
motive engines,  through  crowded  thoroughfares. 

The  fuel  used  on  most  of  the  rail-ways  is  wood,  but 
the  sparks  vomited  out  by  the  chimney  are  a  source  of 
constant  annoyance  to  the  passengers,  and  occasionally 
set  fire  to  the  wooden  bridges  on  the  line,  and  the  houses 
in  the  neighborhood.  Anthracite  coal,  as  formerly  no- 
ticed, has  been  tried,  but  the  same  difficulties  which  at- 
tend its  use  in  steam-boat  furnaces,  are  experienced,  to 
an  equal  extent,  in  locomotive  engines. 

In  situations  where  the  summit-level  of  a  rail-way  can- 
not be  attained,  by  an  ascent  sufficiently  gentle  for  the 
employment  of  locomotive  engines,  or  where  the  forma- 
tion of  such  inclinations,  though  perfectly  practicable, 
would  be  attended  with  an  unreasonably  large  outlay, 
transit  is  generally  effected  by  means  of  inclined  planes, 
worked  by  stationary  engines.  This  system  has  been 
introduced  on  the  Portage  rail-way,  over  the  Alleghany 
Mountains,  in  America,  on  a  more  extensive  scale,  than 
in  any  other  part  of  the  world.  The  Portage  or  Alle- 
ghany rail-way  forms  one  of  tiie  links  of  the  great  Penn 
sylvania  canal  and  rail-road  communication,  from  Phila- 
delphia to  Pittsburg, — a  work  ot  so  difficult  and  vast  a 
nature,  and  so  pecuhar,  both  as  regards  its  situation  and 
details,  that  it  cannot  fail  to  be  interesting  to  every  engi- 
neer, and  I  shall,  therefore,  state  at  some  length  the 
facts  which  I  have  been  able  to  collect  regarding  it. 

This  communication  consists  of  four  great  divisions,  the 
Columbia  rail-road,  the  Eastern  Division  of  the  Penn- 
sylvania canal,  the  Portage    or  Alleghany   railroad,  and 


RAIL-WAYS   IN  THE   UNITED   STATES.  329 

the  Western  Division  of  the  Pennsylvania  canal.  These 
works  form  a  continuous  line  of  communication  from  Phil- 
adelphia, on  the  Schuylkill,  to  Pittsburg,  on  the  Ohio,  a 
distance  of  no  less  than  three  hundred  and  ninety-five  miles. 

Commencing  at  Philadelphia,  the  first  Division  of  this 
stupendous  work  is  the  Philadelphia  and  Columbia  rail- 
road, which  was  opened  in  the  year  1S34.  It  is  eighty- 
two  miles  in  length,  and  was  executed  at  a  cost  of  about 
£666,025,  being  at  the  rate  of  £8122  per  mile.  There 
are  several  viaducts  of  considerable  extent  on  this  rail-way, 
and  two  inclined  planes  worked  by  stationary  engines. 
One  of  these  inclined  planes  is  at  the  Philadelphia  end 
of  the  line.  It  rises  at  the  rate  of  one  in  14.6  for  two 
thousand  seven  hundred  and  fourteen  feet,  overcoming  an 
elevation  of  one  hundred  and  eighty-five  feet.  The  other 
plane,  which  is  at  Columbia,  rises  at  the  rate  of  one  in 
21. '2  for  a  distance  of  one  thousand  nine  hundred  and 
fourteen  feet,  and  overcomes  an  elevation  of  ninety  feet. 
A  very  large  sum  is  expended  in  upholding  the  inclined 
planes,  and  surveys  have  lately  been  made  with  a  view 
to  avoid  them.  The  cost  of  maintaining  the  stationary 
power,  and  superintendence  of  the  Philadelphia  inclined 
plane,  is  said  to  be  about  £8000  per  annum,  and  that  of 
the  Columbia  plane,  about  £3498  per  annum.  Locomo- 
tive engines  are  used  between  the  tops  of  the  inclined 
planes.  The  steepest  gradient  on  that  part  of  the  line  is 
at  the  rate  of  one  in  one  hundred  and  seventeen  ;  but 
the  curves  are  numerous,  and  many  of  them  very  sharp, 
the  minimum  radius  being  so  small  as  three  hundred  and 
fifty  feet.  This  line  of  rail-way  was  surveyed  and  laid 
out,  before  the  application  of  locomotive  power  to  rail- way 
conveyance  had  attained  its  present  advanced  state, — at 
a  period  when  sharp  curves  and  steep  gradients  were  not 
considered  so  detrimental  to  the  success  of  rail-ways,  as 
experience  has  since  shown  them  to  be. 

The  passenger-carriages  on  the  Columbia  rail-road  are 
extremely  large  and  commodious.  They  are  seated  for 
sixty  passengers,  and  are  made  so  high  in  the  roof,  that 
the  tallest  person  may  stand  upright  in  them,  without  in- 
convenience. There  is  a  passage  between  the  seats  ex- 
28* 


330  APPENDIX. 

tending  from  end  to  end,  with  a  door  at  both  extremities  ' 
and  the  coupling  of  the  carriages  is  so  arranged,  tha* 
the  passengers  may  walk  from  end  to  end  of  a  whole 
train,  without  obstruction.  In  winter,  they  are  heated  by 
stoves.  The  body  of  each  of  these  carriages  measures 
from  fifty  to  sixty  feet  in  length,  and  is  supported  on  two 
four-wheeled  trucks,  furnished  with  friction-rollers,  and 
moving  on  a  vertical  pivot,  in  the  manner  formerly  alluded 
to,  in  describing  the  construction  of  the  locomotive  en- 
gines. The  flooring  of  the  carriages  is  laid  on  longitudinal 
beams  of  wood,  strengthened  with  suspension-rods  of  iron. 

At  the  termination  of  the  rail-way  at  Columbia,  is  the 
commencement  of  the  Eastern  Division  of  the  Pennsyl 
vania  canal,  which  extends  to  HolHdaysburg,  a  town  s'lU 
uate  at  the  foot  of  the  Alleghany  Mountains.  This 
canal  is  rather  more  than  one  hundred  and  seventy-two 
miles  in  length,  and  was  executed  at  an  expense  of 
£918,829,  being  at  the  rate  of  <£5342  per  mile.  There 
are  thirty-three  aqueducts,  and  one  hundred  and  eleven 
locks,  on  the  line,  and  the  whole  height  of  lockage  is 
585.8  feet.  A  considerable  part  of  this  canal  is  slack- 
water-navlgatlon,  formed  by  damming  the  streams  of  the 
Juniata  and  Susquehanna.  The  canal  crosses  the  Sus- 
quehanna at  its  junction  with  the  Juniata,  at  which  point 
it  attains  a  considerable  breadth.  x\  dam  has  been  erec- 
ted in  the  Susquehanna,  at  this  place,  and  the  boats  are 
dragged  across  the  river  by  horses,  which  walk  on  a  tow- 
path  attached  to  the  outside  of  a  wooden  bridge,  at  a  lev- 
el of, about  thirty  feet  above  the  surface  of  the  water. 

HolHdaysburg  is  the  western  termination  of  the  East- 
ern Division  of  the  Pennsylvania  canal.  The  town 
stands  at  the  base  of  the  Alleghany  Mountains,  which  ex- 
tend in  a  southwesterly  llrectlon,  from  New  Brunswick, 
to  the  State  of  Alabama,  a  distance  of  upwards  of  eleven 
hundred  miles,  presenting  a  formidable  barrier  to  commu- 
nication between  the  eastern  and  western  parts  of  the 
United  States.  The  breadth  of  the  Alleghany  range  va- 
ries from  a  hundred  to  a  hundred  and  fifty  miles,  but  the 
peaks  of  the  mountains  do  not  attain  a  greater  height  than 
four  thousand  feet  above  the  medium  level  of  the  sea. 


RAIL-WAYS   IN  THE   UNITED   STATES.  331 

They  rise  with  a  gentle  slope,  and  are  thickly  wooded 
to  their  summits.  "  The  Alleghany  Mountains  present 
what  must  be  considered  their  scarp,  or  steepest  side, 
to  the  east,  where  granite,  gneiss,  and  other  primitive 
rocks,  are  seen.  Upon  these  repose,  first,  a  thin  forma- 
tion of  transition  rocks  dipping  to  the  westward,  and  next, 
a  series  of  secondary  rocks,  including  a  very  extensive 
coal  formation."*  The  National  road,  which  has  al- 
ready been  noticed,  was  the  first  line  of  communication 
formed  by  the  Americans  over  tliis  range  ;  and  in  the 
year  1831,  an  Act  was  passed  for  connecting  the  Eastern 
and  Western  Divisions  of  the  Pennsylvania  canal,  by 
means  of  a  rail-road.  This  important  and  arduous  work, 
which  cost  about  £526,871,  was  commenced  within  the 
same  year  in  which  the  Act  for  its  construction  was  grant- 
ed, and  the  first  train  passed  over  it  on  the  26th  of  Novem- 
ber, 1833  ;  but  it  was  not  till  1835,  that  both  the  tracks 
were  completed,  and  the  rail-way  came  into  full  operation. 

The  rail-way  crosses  the  mountains  by  a  pass  called 
*'  Blair's  Gap,"  where  it  attains  its  summit-level,  which  is 
elevated  two  thousand  three  hundred  and  twenty-six  feet 
above  the  mean  level  of  the  Atlantic  ocean.  Mr.  Robin- 
son surveyed  a  line  of  rail-way  from  Philipsburg  to  the 
river  Juniata,  which  is  intended  to  cross  the  Alleghany 
Mountains  by  the  pass  called  "  Emigh's  Gap."  The 
summit-level  of  this  line  is  stated,  in  a  report  by  the  di- 
rectors, to  be  two  hundred  and  ninety-two  feet  lower  than 
that  of  the  Portage  rail- way. 

The  preliminary  operation  of  clearing  a  track  for  the 
passage  of  the  rail-way,  from  a  hundred  to  a  hundred  and 
fifty  feet  in  breadth,  through  the  thick  pine  forests  with 
which  the  mountains  are  clad,  was  one  in  which  no  small 
difiiculties  were  encountered.  This  operation,  which  is 
called  grubbing,  is  litde  know^n  in  the  practice  of  engi- 
neering in  this  country,  and  is  estimated  by  the  Ameri- 
can engineers,  in  their  various  rail- w^ay  and  canal  reports, 
at  from  £40  to  £80  per  mile,  according  to  the  size  and 
quantity  of  the  timber  to  be  removed  ;  an  estimate  which, 
from  the  appearance  of  American  forests,  must,  in  many 

*  Encyclopaedia  Britannica,  article  America. 


332  APPENDIX. 

instances,  be  much  too  low.  The  timber  removed  from 
the  line  of  the  Alleghany  rail-way  is  chiefly  spruce  and 
hemlock  pine,  of  very  large  growth. 

The  line  is  laid  with  a  double  track,  or  four  single  lines 
of  rails,  and  is  twenty-five  feet  in  breadth.  For  a  con- 
siderable distance,  the  rail-way  is  formed  by  side-cutting 
along  steep  sloping  ground,  composed  of  clay-slate,  bitu- 
minous coal,  and  clay,  part  of  the'  breadth  of  the  road  be- 
ing obtained  by  cutting  into  the  hill,  and  part  by  raising 
embankments,  protected  by  retaining  walls  of  masonry. 
The  rail-way  is  consequently  liable  to  be  deluged,  or  even 
entirely  swept  away,  by  mountain  torrents,  and  the  thor- 
ough drainage  of  its  surface  has  been  attended  with  great 
expense  and  difficulty.  The  retaining  walls,- by  which 
the  embankments  are  supported,  are  in  some  places  not 
less  than  a  hundred  feet  in  height ;  they  are  built  of  dry- 
stone  masonry,  and  have  a  batter  of  about  one  half  to 
one,  or  six  inches  horizontal  to  twelve  inches  perpendic- 
ular. There  are  no  parapet  or  fence  walls  on  the  rail- 
way, and  on  many  parts  of  the  line,  especially  at  the  tops 
of  several  of  the  inclined  planes,  the  trains  pass  within 
three  feet  of  precipitous  rocky  faces,  several  hundred 
feet  high,  from  which  the  large  trees,  growing  in  the  ra- 
vines below,  almost  resemble  brushwood.  One  hundred 
and  fifty-three  drains  and  culverts,  and  four  viaducts,  have 
been  built  on  the  rail-way.  One  of  the  viaducts  crosses 
the  river  Conemaugh,  at  an  elevation  of  seventy  feet  above 
the  surface  of  the  water.  There  is  also  a  tunnel  on  the 
line  nine  hundred  feet  in  length,  twenty  feet  in  breadth, 
and  nineteen  feet  in  height. 

The  inclined  planes  are,  however,  the  most  remarka- 
ble works  which  occur  on  this  line.  The  rail- way  extends 
from  Hollidaysburg  on  the  eastern  base,  to  Johnstown  on 
the  western  base,  of  the  Alleghany  Mountains,  a  distance 
of  thirty-six  miles  ;  and  the  total  rise  and  fall,  on  the  whole 
length  of  the  line,  is  2571.19  feet.  Of  this  height,  2007.02 
feet  are  overcome  by  means  of  t^n  inclined  planes,  and 
564.17  feet  by  the  slight  inclinations  given  to  the  parts 
of  the  railway  which  extend  between  these  planes.  The 
distance  from  Hollidaysburg  to  the  summit-level  is  about 


RAIL-WAYS   IN  THE   UNITED   STATES.  333 

ten  miles,  and  the  height  is  1398.31  feet.  The  distance 
from  Johnstown  to  the  same  point  is  about  twenty-six 
miles,  and  the  height  1172.88  feet.  The  height  of  th? 
summit-level  of  the  rail-way,  above  the  mean  level  of  the 
Atlantic,  is  2326  feet. 

The  machinery  by  which  the  inclined  planes  are  work 
ed  consists  of  an  endless  rope  passing  round  horizontal, 
grooved  wheels,  placed  at  the  head  and  foot  of  the  planes 
which  are  furnished  with  a  powerful  break,  for  retarding 
the  descent  of  the  trains.  The  ropes  were  originall}' 
made  seven  and  a  half  inches  in  circumference,  but  they 
have  lately  been  increased  to  eight  inches,  to  prevent  a 
tendency,  which  the)'  formerly  had,  to  slip  in  the  grooved 
wheels,  occasioned  by  their  circumference  being  too  small 
for  the  size  of  the  groove,  or  hollow  in  the  wheel.  Two 
stationary  engines,  of  twenty-five  horses'  power  each,  are 
placed  at  the  head  of  the  inclined  planes,  one  of  which  is 
in  constant  use  in  giving  motion  to  the  horizontal  wheels 
round  which  the  rope  moves,  while  the  trains  are  passing 
the  inclined  planes.  Two  engines  have  been  placed  ar 
each  station,  that  the  traffic  of  the  rail-w^ay  may  not  be 
stopped,  should  any  accident  occur  to  the  machinery  of 
that  which  is  in  operation  ;  and  they  are  used  alternately, 
for  a  week  at  a  time.  Water  for  supplying  the  boilers 
has  been  conveyed,  at  a  great  expense,  to  many  of  the  sta- 
tions, in  wooden  pipes  upwards  of  a  mile  in  length. 

The  planes  are  laid  with  a  double  track  of  rails,  and  an 
ascending  and  a  descending  train  are  always  attached  to 
the  rope  at  the  same  time.  Many  experiments  have  been 
made,  to  procure  an  efficient  safety-car,  to  prevent  the 
trains  from  running  to  the  foot  of  the  inclined  plane,  in 
the  event  of  the  fixtures,  by  which  they  are  attached  to 
to  the  endless  rope,  giving  way.  Several  of  these  safety- 
cars  are  in  use,  and  are  found  to  be  a  great  security.  The 
trains  are  attached  to  the  endless  rope  simply  by  two  ropes 
of  smaller  size  made  fagt  to  the  couplings  of  the  first  and 
last  wagons  of  the  train,  and  to  the  endless  rope  by  a 
hitch  or  knot,  formed  so  as  to  prevent  it  from  slipping. 

Locomotive  engines  are  used  on  the  parts  of  the  road 
between  the  inclined  planes. — Stevenson^ s  '  Sketch  of 
Civil  Engineering  in  J^orth  America.'' 


334 


APPENDIX, 


Table  of  the  Principal  Rail-ways  in  operation  in  the 
United  States,  in  1840. 


NAME. 

counsE. 

When 

Length 

Whole 
length 

a. 

opened 

Miles. 

in  each 
State. 

Maine. 

Bangor  and  Orono,     . 

From  Bangor  to  Orono, 

1836 

10 

10 

New  Hampshire. 

Nashua  and  Lowell, 

Nashua  to  Lowell, 
Massachusetts. 

1838 

15 

1 
15      ! 

Quincy, 

C  Quincy  Quarries  to  Nepon- 
l    set  River,    . 

J  1827 

4 

Boston  and  Lowell,    . 

Boston  to  Lowell,  . 

1835 

26 

Andovcr  and  Wilmington, 

C  Andover  to  the  Boston  and 
I    Lowell  Rail-road, 

|l836 

n 

Andover  and  Haverhill, 

Andover  to  Haverhill,     . 

1838 

10 

Boston  and  Providence, 

Boston  to  Providence, 

1835 

41 

Dedham  Branch,    . 

C  Boston  and  Providence  R. 
\    Road  to  Dedham,      . 

|l835 

2 

Taunton  Branch, 

C  Boston     and     Providence 
I    Rail-road  to  Taunton, 

1  1836 

11 

Boston  and  Worcester, 

Boston  to  Worcester,     . 

1835 

45 

Western  Rail-way,     . 

Worcester  to  Springfield, 

1839 

54 

Worcester  and  Norwich, 

Worcester  to  Norwich, 

1839 

59 

Eastern  Rail-road, 

Boston  to  Newburyport, 

1839 

36 

2951 

Rhode  Island. 

Providence  &  Stonington, 

Providence  to  Stonington, 

1837 

47 

47 

Connecticut. 

Hartford  and  New  Haven, 

Hartford  to  New  Haven, 

1839 

40 

Housatonic, 

Bridgeport  to  New  Milford, 

•    • 

40 

New  York. 

80 

1  Mohawk  and  Hudson, 

C  Between   the   Rivers   Mo- 
l    hawk  and  Hudson,     . 

|l832 

16 

Saratoga  &  Schenectady, 

Saratoga  to  Schenectady, 

1832 

22 

Rochester,  . 

Rochester  to  Carthage, 

1833 

3 

Ithaca  and  Oswego, 

Ithaca  to  Oswego,   . 

1834 

29 

1  Rensselaer  and  Saratoga, 

Troy  to  Ballston, 

1835 

24^ 

iUtica  and  Schenectady, 

Utica  to  Schenectady,     . 

1836 

77 

j Buffalo  and  Niagara,    . 

Buffalo  to  Niagara  Falls, 

1837 

21 

'Haerlem, 

New  York  to  Haerlem, 

1837 

7 

iLockport  and  Niagara, 

Lockport  to  Niagara  Falls, 

1837 

24 

i  Brooklyn  and  Jamaica, 

Brooklyn  to  Jamaica, 

1837 

12 

JAuburn  and  Syracuse, 

Auburn  to  Syracuse, 

.    . 

26 

jCatskill  and  Canajoharie, 

Catskill  to  Canajoharie, 

68 

Hudson  and  Berkshire, 

C  Hudson  to  the  Boundary  of 
I    Massachusetts, 

i' 

30 

Tonawanda, 

Rochester  to  Attica, 

45 

404^ 

New  Jersey. 

Camden  and  Amboy, 

Camden  to  Amboy, 

1832 

61 

Paterson,     . 

Paterson  to  Jersey,     . 

1834 

16i 

1  New  Jersey,  . 

C  Jersey  City  to  New  Bruns- 
l    wick, 
Morristown  to  Newark, 

jl836 

31 

Morris  and  Essex, 

.    . 

20 

PennsylvanA.. 

128i 

jColumbia,   . 

Philadelphia  to  Columbia, 

. 

82 

Alleghany,      ... 

CHollidaysburg    to    Johns- 
\  town,  over  the  Alleghanies, 

}•    • 

36 

Mauch  Chunk,     . 

C  Mauch  Chunk  to  the  Coal- 
l    mines,    .... 

J  1828 

5 

Room  Run,     . 

Mauch  Chunk  to  the  mines, 
Carried  forward, 

■    ■ 

5k 

128i 

1980* 

RAIL-WAYS   IN  THE  UNITED   STATES. 


335 


NAME. 

COURSE. 

When 

Length 
in 

Whole 

length 

opened 

Miles. 

in  each 
State. 

Brought  forward,'" 

■•   . 

12Si 

960J 

Pennsylvania,  contirf^ed. 

Mount  Carbon,   . 

MountCarbon  to  the  mines,     1830 

7^ 

Schuylkill  Valley,  . 

(Port  Carbon  to  Tuscarora,'  ) 
I   with  numerous  branches,  5  "    * 

30 

Schuylkill,  . 

13 

Mill  Creek,     .        . 

Port  Carbon  to  Mill  Creek, 

, 

7 

xMinehill  and  Schuylkill, 

20 

Pine-grove, 

Pine-grove  to  Coal-mines, 

4 

Little  Schuylkill,   . 

Port  Clinton  to  Tamaqua, 

isai 

23 

Lackawaxen,.     . 

C  Lackawaxen  Canal  to  the 
I    River  Lackawaxen, 

I-  • 

16J 

Westchester, 

C  Westchester  to  Columbia 
I   Rail-road,  . 

h832 

9 

Philadelphia  and  Trenton, 

Philadelphia  to  Trenton, 

1833 

26i 

Philadelphia&Norristown 

Philadelphia  to  Xorristown 

1837 

19 

Central  Rail-way, 

Pottsville  to  Danville, 

51J 

Philadelphia  and'  Reading, 

Philadelphia  to  Reading, 

•    • 

40  i 

Philadelphia  &  Baltimore, 

Philadelphia  to  Baltimore, 

93 

489 

Delaware. 

Newcastle  &  Frenchtown, 

Newcastle  to  Frenchto^m, 

1832 

16 

16 

Maryland. 

Baltimore  and  Ohio, 

C  Completed   to   Harper's 
I    Ferry,  with  branches, 

J  1835 

86 

Winchester, 

C  Harper's    Ferry   to    Win- 
l    Chester, 

30 

Baltimore  &  Port-Deposit, 

Baltimore  to  Port-Deposit, 

34i 

Baltimore  &  Washington, 

Baltimore  to  Washington, 

i83.5 

40 

Baltimore  &  Susquehanna, 

Baltimore  to  York,     . 
Virginia. 
(Richmond  to  Chesterfield 
(    Coal-mines,  . 

1837 

59i 

249* 

Chesterfield, 

13 

Petersburg  and  Roanoke, 

(  Petersburg  to  Blakely,  on 
I    the  Roanoke,     . 

59 

Winchester  and  Potomac, 

(Winchester  to   Harper's 

\    Ferry,     .... 

Portsmouth  to  Weldon, 

30 

Portsmouth  and  Roanoke, 

T7i 

Richmond,   Fredericks-  ? 
burg,  and  Potomac,        j 

(Richmond    to    Fredericks- 
l   burg,   .... 

58 

Manchester, 

Richmond  to  Coal-mines, 
South  Carolina. 

13 

250i 

South  Carolina  Rail-road, 

(  Charleston  to  Hamburg  on 
I   the  Savannah, 
Georgia. 

|l833 

136 

136 

Alatamaha  «fe  Brunswick, 

Alatamaha  to  Brunswick, 

•    • 

12 

12 

Alabama. 

Tuscumbia  and  Decatur, 

( Mussel-Shoals,    Tennessee 
I   River, 

Louisiana. 

46 

46 

Pen  tchar  train, 

(  New  Orleans  to  Lake  Pont- 
\   chartrain. 

|l831 

5 

Carrollton, 

New  Orleans  to  Carrollton, 
Kentucky. 

' 

6 

11 

Lexington  and  Ohio,      . 

Lexington  to  Frankfort, 

29 

Frankfort  and  Louisville, 

1 

Frankfort  to  Louisville, 
Total  length  in  miles, 

50 

79 
2270 

S36 


APPENDIX. 


List  of  the  other  Rail-ways  now  in  progress  in  ths 
United  States. 


Haverhill  and  Exeter, 
Newburyport  and  Ports- 
mouth, 


Old  Colony, 
Western, 


Western,     . 


Long  Island, 

New  York  and  Erie, 

Saratoga  and  Washington, 


Elizabethtown&Belvidere 
Burlington  &Mount  Holly. 


Oxford, 
Tioga, 


Greensville  and  Roanoke, 
Charleston  and  Cincinnati, 


Augusta  and  Athens,  . 
Macon  and  Forsyth, 
Central  Rail-road, 


Montgomery  and  Chat-  i 
tahoochee,        .        .    . ' 


Mississippi  Rail-road.    . 

Bowling  Green  and  Bar- ) 
ren  River,  .        .     > 


Mu-i  River  and  Lake  Erie, 
Sandusky  &  Monroeville, 


Detroit  and  St.  Joseph, 


New  Hampshire. 
Haverhill  to  Exeter, 
Newburyport  to  Portsmouth,     . 

Massachusetts. 
Taunton  to  New  Bedford, 
Springfield  to  New  York  line,     . 

Connecticut. 

Hartford  to  Springfield, 

New  York. 

Jamaica  to  Greenport, 
New  York  to  Lake  Erie, 
Saratoga  to  Whitehall, 

New  Jersey. 
Elizabethtown  to  Belvidere, 
Burlington  to  Mount  Holly,    . 

Pennsylvania. 

Columbia  Rail-road  to  Port  Deposit, 
Chemung  Canal  to  Tioga  Coal-mines, 

Virginia. 

South  Carolina. 
Charleston  to  Cincinnati,    . 

Georgia. 
Augusta  to  Athens,       .        .        .        . 
Macon  to  Forsyth,    .... 
Savannah  to  Macon,     .        .        .        . 

Alabama. 

Mississippi. 
Natchez  to  Canton, 

Kentucky. 
Bowling  Green  to  Barren  Biver,    . 

Ohio. 
Dayton  to  Sandusky,    .... 
Sandusky  to  Monroeville, 

Michigan. 
Detroit  to  the  River  St.  Joseph, 
Total  length, 


MANUFACTURE  OF  MAPLE  SUGAR.       337 


VI. — Manufacture  of  Maple  Sugar. 

The  following  account  of  the  manufacture  of  sugar, 
from  the  sap  of  the  maple  tree,  is  copied  from  the 
North  American  Sylva  of  Michaux. 

The  work  is  commonly  taken  in  hand  in  the  month  of 
February,  or  in  the  beginning  of  March,  while  the  cold 
continues  intense,  and  the  ground  is  still  covered  with 
snow.  The  sap  begins  to  be  in  motion  at  this  season, 
two  months  before  the  general  revival  of  vegetation.  In 
a  central  situation,  lying  convenient  to  the  trees,  from 
which  the  sap  is  drawn,  a  shed  is  constructed,  called,  a 
sugar-camp,  which  is  destined  to  shelter  the  boilers,  and 
the  persons  who  attend  them,  from  the  weather.  An 
auger, three  quarters  of  an  inch  in  diameter,  small  troughs 
to  receive  the  sap,  tubes  of  elder  or  sumac,  eight  or  ten 
inches  long,  corresponding  in  size  to  the  auger,  and  laid 
open  for  a  part  of  their  length,  buckets  for  emptying  the 
troughs  and  conveying  the  sap  to  the  camp,  boilers  of 
€fteen  or  eighteen  gallons  capacity,  moulds  to  receive  the 
sirup  when  reduced  to  a  proper  consistency  for  being 
<"ormed  into  cakes,  and,  lastly,  axes  to  cut  and  split  the 
fuel,  are  the  principal  utensils  employed  in  the  operation. 

The  trees  are  perforated  in  an  obliquely  ascending  di- 
rection, eighteen  or  twenty  inches  from  the  ground,  with 
two  holes,  four  or  five  inches  apart.  Care  should  be  tak- 
en that  the  augers  do  not  enter  more  than  half  an  inch 
within  the  wood,  as  experience  has  shown  the  most  abun- 
dant flow  of  sap  to  take  place  at  this  depth.  It  is  also 
recommended  to  insert  the  tubes  on  the  south  side  of  the 
tree  ;  but  this  useful  hint  is  not  always  attended  to. 

The  troughs,  which  contain  two  or  three  gallons,  are 
made  in  the  Northern  States,  of  white  pine,  of  white 
or  black  oak,  or  of  maple  ;  on  the  Ohio,  the  mulberry, 
which  is  very  abundant,  is  preferred.  The  chestnut, 
the  black  walnut,  and  the , butternut  should  be  rejected, 
as  they  impart  to  the  liquid  the  coloring  matter  and  bitter 
principle,  with  which  they  are  impregnated. 

A  trough. is  placed  on  the  ground,  at  the  foot  of  each 
tree,  and  the  sap  is,  every  day,  collected  and  temporarily 
II.  20  XII. 


338  APPENDIX. 

poured  into  cask  J,  from  which  it  is  drawn  out  to  fill  the 
boilers.  The  evaporation  is  kept  up  by  a  brisk  fire,  and 
the  scum  is  carefully  taken  ojBf  during  this  part  of  the  ])ro- 
cess.  Fresh  sap  is  added,  from  time  to  time,  and  the 
heat  is  maintained,  till  the  liquid  is  reduced  to  a  sirup, 
after  which  it  is  left  to  cool,  and  then  strained  through  a 
blanket,  or  other  woollen  stuff,  to  separate  the  remaining 
impurities. 

Some  persons  recommend  leaving  the  sirup,  twelve 
hours,  before  boiling  it  for  the  last  time  ;  others  proceed 
with  it  immediately.  In  either  case,  the  boilers  are  only 
half  filled,  and  by  an  active,  steady  heat,  the  hquor  is 
rapidly  reduced  to  the  proper  consistency  for  being  poured 
into  the  moulds.  The  evaporation  is  known  to  have  pro- 
ceeded far  enough,  when,  upon  rubbing  a  drop  of  the 
sirup  between  the  fingers,  it  is  perceived  to  be  granular. 
If  it  is  in  danger  of  boihng  over,  a  bit  of  lard  or  of  but- 
ter is  thrown  into  it,  which  instantly  calms  the  ebullition. 
The  molasses  being  drained  off  from  the  moulds,  the 
sugar  is  no  longer  dehquescent,  like  the  raw  sugar  of  the 
West  Indies.  Maple  sugar, manufactured  in  this  way,  is 
lighter  colored,  in  proportion  to  the  care  with  which  it  is 
made,  and  the  judgement  wnh  which  the  evaporation  is 
conducted.  It  is  superior  to  the  brown  sugar  of  the 
Colonies,  at  least,  to  such  as  is  generally  used  in  the 
United  States  ;  its  taste  is  as  pleasant,  and  it  is  as  good 
for  culinary  purposes.  When  refined,  it  equals  in  beauty 
the  finest  sugar  consumed  in  Europe. 

The  sap  continues  to  flow  for  six  weeks  ;  after  which, 
it  becomes  less  abundant,  less  rich  in  saccharine  matter, 
and  sometimes  even  incapable  of  crystallization.  In  this 
case,  it  is  consumed  in  the  state  of  molasses,  which  is 
superior  to  that  of  the  West  India  Islands.  After  three 
or  four  days  exposure  to  the  sun,  maple  sap  is  converted 
into  vinegar,  by  the  acetous  fermentation. 

The  amount  of  sugar  manufactured  in  a  year  varies, 
from  different  causes.  A  cold  and  dry  winter  renders 
the  trees  more  productive  than  a  changeable  and  humia 
season.  It  is  observed,  that  when  a  frosty  night  is  follow- 
ed by  a  dry  and  brilliant  day,  the  sap  flows  abundantly  : 


MANUFACTURE   OF  BEET   SUGAR  339 

and  two  or  three  gallons  are  sometimes  yielded  oy  a  single 
tree,  in  twenty-four  hours.  Three  persons  are  found 
sufficient  to  tend  two  hundred  and  fifty  trees,  which  give 
one  thousand  pounds  of  sugar,  or  four  pounds  from  each 
tree.  But  this  product  is  not  uniform,  for  many  farmers 
on  the  Ohio  do  not  commonly  obtain  more  than  two 
pounds  from  a  tree. 

Trees,  which  grow  in  low  and  moist  places,  afford  a 
greater  quantity  of  sap,  than  those,  which  occupy  rising 
grounds,  but  it  is  less  rich  in  the  saccharine  principle. 
That  of  insulated  trees,  left  standing  in  the  middle  of 
fields,  or  by  the  side  of  fences,  is  the  best.  It  is  also  re- 
marked, that  in  districts  which  have  been  cleared  of  othei 
trees,  and  even  of  the  less  vigorous  sugar  maples,  the  pro- 
duct of  the  remainder  is  proportionally  more  considerable. 

VII. — Of  the  Manufacture  of  Beet  Sugar. 

The  following  account  of  this  manufacture,  in  France, 
is  extracted  from  a  work  compiled,  in  1836,  by  Mr.  Ed- 
ward Church. 

Cleansing  of  the  Beet  Roots. 

The  object  of  this  operation  is,  to  separate  from  the 
loots  the  green  parts  of  the  neck,  w^hich  may  not  have 
been  removed,  the  radicles,  the  defective  parts,  and  the 
earth  and  the  gravel  which  may  adhere  to  these  ;  when 
this  is  properly  done,  the  washing,  should  it  be  required, 
(which  is  not  the  case  in  many  places,)  is  easily  and 
quickly  performed.  In  all  cases,  the  cleansing  should  be 
effectually  done,  otherwise  the  gravel  and  earth  (should 
there  any  remain)  will  injure  the  rasps.  "Women  and 
children  perform  this  operation  in  France.  For  this  pur- 
pose, each  hand  is  provided  with  a  sharp  knife,  from  two 
to  three  inches  broad,  and  ten  long.  With  this  tool, 
seated  near  a  pile  of  beets,  the  laborer  takes  the  beets  one 
after  another,  scrapes  them  lengthwise,  to  detach  the  earth 
and  stones,  takes  off  the  neck  all  round,  and  even  a  thin 
shce,  when  this  has  not  been  already  done. 

When  a  beet  is  too  large  to  be  applied  conveniently  to 
the  rasp,  the  workmen  should  cut  it  in  two,  or  in  quarters, 


340  APPENDIX. 

according  to  its  dimeisions.  This  must  always  be  done 
longitudinally. 

The  cleaning  of  the  beets  should  always  take  place  in  a 
room  near  the  rasps  and  presses,  in  order  that  these  dif- 
ferent operations  may  follow  conveniently  and  quickly. 
The  place  should  be,  w^hen  possible,  a  building  sufficient- 
ly large  to  contain  beets  enough  for  the  consumption  of 
the  works  for  at  least  four  or  five  days,  and  leave  room 
enough  besides  for  the  laborers  to  do  their  w^ork  easily. 
As  fast  as  the  roots  are  cleansed,  they  should  be  thrown 
into  baskets  about  eighteen  inches  high,  and  a  foot  w-ide, 
of  a  conical  shape,  with  handles.  When  several  of  these  are 
filled  they  are  carried  to  the  rasp  ;  there  they  leave  the 
full  baskets  and  take  back  the  empty  ones.  Two  women, 
in  France,  who  understand  their  business,  can  clean  easily 
from  three  to  three  and  one  half  tons  of  roots  in  twelve 
hours'  work,  and  carry  them  to  the  rasp.  The  wages  of 
these  women,  in  some  parts  of  France,  do  not  exceed 
twelve  or  fifteen  cents  each,  per  day  ;  at  this  rate,  the 
cleaning  of  a  ton  of  beets  would  not  cost  over  ten  cents. 
It,  of  course,  reduces  the  weight  of  the  beet  ;  the  loss  is 
estimated,  usually,  at  from  six  to  seven  per  cent. 

The  operation  of  washing  the  roots  is,  (as  we  before 
said,)  by  no  means  generally  requisite  ;  and  a  careful 
cleansing,  as  described  above,  is  decidedly  preferable,  and 
it  is  not  always,  that  water  in  sufficient  quantity  can  be  con- 
veniently obtained.  When  a  little  stream  is  at  hand,  and 
they  can  be  placed  in  baskets  in  the  water,  and  remain  till 
the  earth  is  washed  off  by  its  motion,  such  a  peculiar  ad- 
vantage should  never  be  neglected  ;  but  this  of  rare  occur- 
rence. 

This  washing  is  the  more  difficult,  too,  as  it  must  be 
executed  in  the  winter,  and  the  water  frequently  may  be 
frozen.  A  general  opinion  once  prevailed,  that  the  cleans- 
ing with  water  was  indispensable,  and  that  the  manufacture 
of  sugar  could  not  be  undertaken  without  a  locality  which 
supplied  an  abundance  of  it  ;  but  this  supposed  necessity 
is  groundless,  for  there  are  few  spots  where  a  sufficiency 
of  water  may  not  be  found  for  the  inconsiderable  wants  of 
a  beet  sugar  manufactory. 


MANUFACTURE   OF  BEET  SUGAR.  341 


Rasping  the  Beets. 

The  first  idea  of  the  famous  Achard,  when  in  search  of 
the  best  mode  of  extracting  the  sugar  from  beets,  was  to 
boil  them  and  reduce  them  to  paste  ;  but  he  soon  found 
insuperable  difficulties  in  the  way  of  this  process.  The 
simple  pressure  without  rasping  has  been  repeatedly  tried, 
and  recently  again  by  an  improved  press,  and  the  rasp  is 
as  yet  the  only  effectual  mode  employed,  and  too  much 
care  cannot  be  used  in  having  this  operation  well  done,  as 
on  it  depends,  in  a  great  measure,  the  more  or  less  sugar 
that  is  obtained.  The^e  is  a  great  diversity  in  the  con- 
struction of  this  machine,  but  the  cylindrical  rasp'of  Mo- 
lard  appears  to  have  the  preference.  The  cylinder  is  of 
cast-iron,  into  which  one  hundred  and  twenty  saw  plates 
are  inserted.  Asa  description  of  this  would  probably  be 
unintelligible  without  a  representation  of  it  by  an  engrav- 
ing, I  will  not  attempt  it.  A  man  presses  the  beets  en- 
closed in  a  box  against  the  circumference  of  the  cyhnder, 
another  w^orkman,  on  the  opposite  side  of  the  machine,  re- 
moves the  pulp,  and,  with  the  ladle  with  which  he  removes 
it,  fills  bags,  as  we  shall  more  particularly  explain  hereaf- 
ter. From  eighty  to  one  hundred  pounds  of  beet  are  re- 
duced to  pulp,  in  one  minute. 

The  rasping  requires,  as  well  as  every  other  operation 
of  this  manufacture,  great  activity  ;  and,  as  much  as  possi- 
ble, the  rasping  more  beets  than  are  immediately  wanted, 
must  be  avoided,  as  a  prejudicial  change  takes  place  in 
the  pulp,  from  a  quarter  to  a  half  hour,  at  most,  after  it  is 
'produced.  A  blackish  color,  which  gradually  increases,  is 
the  indication  of  this  change.  It  is  therefore  prudent  that 
no  more  should  be  rasped  than  can  be  immediately  pressed. 
The  rasp  must  be  kept  perfectly  clean  by  repeated  wash- 
ings. Once  a  day,  at  least,  every  part  of  the  machine,  and 
all  the  tools  appertaining  to  it,  should  be  carefully  cleansed, 
because  every  portion  of  juice,  or  pulp,  which  is  suffered 
to  remain  on  them,  would  soon  serve  as  a  leaven  to  excite 
fermentation. 

It  is  immaterial  what  power  is  used  to  drive  the  rasps ; 
29* 


342  APPENDIX. 

animal,  water,  and  steam,  power,  and  even  wind,  is  some- 
limes  used  in  France. 

Extraction  of  the  Beet  Juice. 

A  variety  of  machines,  and  of  power,  has  been  used, 
for  the  pressing  of  the  pulp,  as  well  as  for  raspjng  the 
roots.  Of  late  the  Hydraulic  press  has  superseded  almost 
every  other,  for  this  last  operation,  at  least,  in  large  man- 
ufactories. The  pulp,  enclosed  in  bags,  is  submitted  to 
the  action  of  this  machine  ;  the  bags  are  usually  made  of 
Russia  duck.  The  cloth,  though  required  to  be  strong, 
must  not  be  so  close  that  the  juice  cannot  easily  pass 
through  it,  or  they  will  otherwi^  burst  ;  on  the  other 
hand,  it  must  be  sufficiently  so,  to  prevent  the  pulp 
passing  through  the  tissue. 

This  last  defect,  however,  is  less  to  be  feared  than  the 
first,  so  that  the  caution,  most  to  be  attended  to,  is,  to 
avoid  too  close  a  texture  ;  and  it  must  be  recollected  that 
it  will  become-closer  when  saturated  with  the  juice.  The 
size  of  the  bags  may  be  varied,  but,  generally  speaking, 
half  a  yard  wide  and  one  yard  long  is  a  convenient  di- 
mension ;  they  should  not  be  more  than  three  fourths  filled. 
The  bags  must  be  kept  perfectly  clean,  and  they  should 
be  washed  every  day  in  boiling  water^  with  a  small  addi- 
tion of  the-sub-carbonate  of  soda.  Wicker-work  frames, 
on  which  the  bags  are  to  be  piled,  must  be  provided  ; 
they  should  be  made  strong,  and  proportioned  to  the  size 
of  the  platform  of  the  press,  that  is,  of  the  same  dimen- 
sions ;  they  serve  to  support  the  piles  of  bags  in  their 
vertical  position,  on  the  hand-wagon,  with  which  they  are 
removed  from  the  rasp  to  the  press,  and  are  themselves 
kept  in  place,  when  on  the  press,  by  stanchions,  fixed  to 
the  platform  of  the  press  at  the  lower  end,  the  other 
sliding  through  a  groove  fixed  to  the  frame-work.  These 
wicker- frames  and  bags  are  placed  alternately  under  the 
press,  usually  to  the  number  of  thirty  of  each.  As  re- 
gards these  frames,  the  caution  of  the  cleanliness  is  re- 
newed, and,  in  a  word,  must  be  applied  to  every  branch 
of  this  manufactory. 

A  Reservoir  is  next  to  be  provided,  to  receive  the 


MANUFACTURE   OF  BEET   SUGAR.  343 

juice  from  the  press,  to  be  subsequently  conveyed  to  the 
defecating  boiler  ;  it  must  be  supplied  with  pipes  of  com- 
munication with  the  press,  and  a  pump  to  convey  the 
juice  it  contains  to  the  defecating  boiler  ;  it  should  be 
placed  on  a  lower  level  than  the  press,  and  receive  the 
juice  by  an  inclined  plane.  It  must  be  made  substantial- 
ly of  wood,  and  lined  wnth  copper,  having  a  concavity  in 
the  centre,  into  which  the  bottom  of  the  pump  must  be 
inserted,  so  as  to  empty  it  completely.  The  capacity 
must,  of  course,  depend  on  the  extent  of  the  manufactory. 

Mode  of  operating  with  the  Press. 

When  the  bags  and  wicker-frames  have  been  pded  as 
before  described,  alternately,  to  the  number  of  thirty  or 
more  of  each,  on  the  platform,  and  the  stanchions  placed, 
the  weight  of  the  pulp  alone  causes  a  pretty  plentiful  flow 
of  juice  ;  if  the  press  used  is  a  screw  press,  a  workman 
takes  hold  of  the  lever,  and  turns  it,  then  a  second  man 
assists,  and  then  a  third.  When  they  have  exerted  their 
united  strength  on  the  lever,  the  job  is  done,  and,  after  al- 
lowing the  bags  to  drain,  whilst  they  are  filling  others, 
the  press  is  unscrewed,  the  bags  removed,  the  pulp  cakes 
disposed  of,  the  bags  cleansed,  and  the  operation  first  de- 
scribed is  continued,  till  the  whole  quantity  of  pulp  pre- 
pared is  disposed  of. 

Defecation  of  the  Juice. 

The  juice  of  the  beet,  as  it  comes  from  the  press,  car- 
ries with  it  all  the  soluble  parts  of  the  root.  It  contains, 
in  this  state,  not  only  sugar  and  icater,  but  other  compo- 
nent parts,  which  cannot  be  separated  by  evaporation 
alone  ;  they  must  be  precipitated  by  chemical  agents.  Ma- 
ny and  experfiive  experiments  were  made  in  search  for 
these,  which  I  shall  not  here  attempt  to  explain.  The 
present  process  is  as  follows  :  Suppose  a  boiler  contain- 
ing four  hundred  gallons  of  juice  ;  add,^e/o?'e  lighting  the 
fire,  eight  pounds  sulphuric  acid  at  sixty-six  degrees,  one 
part  acid,  three  parts  water,  diluted,  mix  quickly  and 
thoroughly  with  the  juice,  then  take  nine  pounds  of  quick- 
lime, weighed  before  it  is  slaked,  then  slake  with  warm 


344  APPENDIX. 

water  to  the  consistency  of  milk,  throw  this  also  into  the 
juice,  and  stir  the  whole  completely ;  the  fire  is  now  to 
be  kindled  under  the  boiler,  and  its  contents  raised  to  the 
temperature  of  one  hundred  and  ninety  degrees  of  Fah- 
renheit ;  then  animal  carbon,  that  has  been  employed  in 
clarification,  is  added,  and  well  mixed,  and  a  portion  of 
diluted  ox  blood  stirred  in  carefully  ;  the  fire  is  withdrawn, 
the  juice  allowed  to  settle,  and  is  drawn  off  clear,  through 
a  cock  placed  near  the  bottom  of  the  boiler.  It  is  im- 
portant to  observe  that  the  juice,  when  the  sulphuric  acid 
is  added,  must  not  be  warm.  This  process  has  failed  in 
the  hands  of  some  imitators  of  M.  Crespel,  from  a  mis- 
take on  this  point.  M.  Dubrunfaut  acknowledges  that  he 
himself  committed  it. 

Concentration  of  the  Juice. 

For  this  purpose,  one  or  more  boilers  are  necessary, 
with  which  the  evaporation  is  begun  and  finished  ;  in  these 
the  juice  from  the  defecating  boiler  is  received  clear  ; 
then  a  slow  fire  is  kept  up  m  the  beginning,  and  some  al- 
buginous  matter,  (white  of  eggs,  or  blood,)  added,  if  it 
should  seem  to  be  required.  After  this,  a  man  must  at- 
tend closely  to  the  boiler,  and  manage  the  fire.  When  froth 
appears,  it  will  be  his  duty  to  throw  a  small  piece  of  but- 
ter, or  other  grease,  (which  he  should  have  near  him,)  into 
the  vessel,  which  will  immediately  cause  it  to  subside  ;  he 
should  also  have  a  ladle  to  stir  it  when  required.  When 
th()  juice  has  reached  the  proper  point,  that  is  to  say, 
twenty-six  degrees  of  Baumes's  areometer,  when  boiling, 
that  is  thirty  degrees,  when  cold,  it  is  time  to  proceed  to 
the  operation  of  clarifying. 

Clarifying. 

The  object  of  this  is,  to  separate  the  sirup  concen- 
trated to  thirty  degrees,  or  near  it,  from  the  extraneous 
matter  which  it  Rolds  in  suspension,  and  moreover  to  de- 
prive it,  by  clarifying  agents,  of  all  coloring  matter,  and 
other  foreign  substances  which  ivere  in  the  juice,  or  have 
formed  there  whilst  under  the  preceding  operation,  all 
which  matter  is  injurious  to  the  sugar.      Clarification  mav 


MANUFACTURE   OF  BEET   SUGAR.  345 

be  divided  into  two  distinct  branches,  the  one  chemical, 
having  for  its  object,  by  clarifying  agents,  such  as  animal 
carbon,  albumine,  &c.,  to  purify  the  sirup  ;  the  other,  me- 
chanical, having  for  its  object  to  separite  from  the  same, 
the  carbon  and  other  sohd  bodies  agglomerated  by  the  al- 
bumine. 

The  first  is  managed  with  a  boiler,  only  because  the 
action  of  the  chemical  agents  employed  require  to  be 
aided  by  heat 

Of  all  the  means  hitherto  devised  for  clarification,  none 
has  been  found  so  simple  and  so  effective  as  that  offered 
by  the  use  of  animal  carbon,  and  albuginous  or  caseous 
matter.* 

We  will  here  suppose  that  the  object  in  view  is  to 
clarify  the  portion  of  sirup,  supphed  by  the  defecation  of 
one  hundred  gallons  of  juice,  that  is,  sixteen  and  a  half 
gallons  of  sirup  concentrated  to  twenty-six  degrees  boil- 
ing and  thirty  degrees  cold  ;  (it  follows  that  for  any  other 
quantity  it  is  only  required  to  follow  the  same  proportion  ;) 
to  do  this,  we  must  proceed  to  weigh  eight  pounds  of  ani- 
mal carbon,  and  throw  it  into  the  boiler  ;  the  sirup,  when 
boiling,  should  be  well  stirred  with  the  ladle,  then  with  the 
skimmer  ;  the  black  agglomerated  matter  which  rises  to 
the  surface  should  be  broken  up,  and  mixed  again  with  the 
liquid  ;  when  it  is  apparent  that  the  carbon  is  sufficiently 
separated  and  mixed  with  the  sirup,  it  may  be  left  to  boil 
for  a  few  minutes.  The  sirup  now  assumes  a  turbid  and 
murky  appearance  ;  whilst  this  operation  is  proceeding,  s 
quart  of  ox  blood,  or  the  white  of  four  eggs,  should  be 
beat  up,  and  diluted  with  water,  or  otherwise,  two  quarts- 
of  skimmed  milk-  This  mixture  must  now  be  thrown  into 
the  boiler,  taking  care  to  mix  the  whole,  well  together. 
The  ebullition  will,  of  course,  have  been  stopped  by  this 
addition  ;  and  it  is  proper,  till  it  begins  again  to  boil,  tiiat  it 
should  be  constantly  stirred,  to  prevent  the  precipitation 
of  the  ingredients  ;  the  ebullition  must  be  kept  up  for  a 
few  minutes,  and  the  sirup  is  then  prepared  for  filtration. 

*  The  process  we  are  about  to  describe  is  varied  by  different  man 
ufacturers.  By  some,  the  acid  is  omitted  altogether,  and  other  agents 
■ubstituted. 


vM6  APPENDIX. 


Filtration. 


This  is  an  exceedingly  simple  operation  ;  a  flannel  cloth 
fixed  to  a  frame  is  all  that  is  required. 

Sirup  at  the  density  of  thirty  degrees  cold,  as  it  comes 
from  the  filterer,  is  not  sufficiently  concentrated  to  crystal- 
lize ;  it  is  therefore  necessary  to  submit  it  to  another  boil- 
ing, to  evaporate  the  superabundant  water  it  still  contains, 
and  so  to  produce  the  required  crystallization. 

This  operation  is  only  a  continuation  of  the  concentra- 
ting process,  and  also  its  completion  ;  the  same  boiler, 
which  is  suitable  for  the  first  part  of  this  process,  is  the 
one  now  again  required,  the  fire  must  be  carefully  attend- 
ed to,  the  sirup  skimmed  when  required,  and,  if  it  rises  in 
foam,  must  be  stopped,  as  before,  by  a  piece  of  grease ; 
when  the  proof  shows  ninety  and  one  half  to  ninety-one 
of  Reaumer,  two  hundred  and  thirty-six  degrees  Fahren- 
heit, which  point  it  may  reach,  if  the  sirup  is  very  good, 
it  is  time  to  stop  and  empty  the  boiler.  It  would  be  more 
prudent  to  do  so  at  eighty-nine  and  one  half;  the  sugar 
would  purify  more  easily,  and,  as  the  molasses  must  neces- 
sarily be  reboiled,  this  supports  the  operation,  all  the  bet- 
ter, for  being  a  little  richer  in  sugar. 

The  sixteen  and  one  half  gallons,  with  which  we  began 
our  experiment,  will  new  be  reduced  to  ten  and  one  half 
gallons.  In  this  state  it  may  be  turned  into  a  vessel,  to 
cool  gradually,  where  it  may  stay  for  ten  or  twelve  hours, 
when  it  will  fall  to  the  temperature  of  one  hundred  and 
seventy  degrees,  or  one  hundred  and  eighty  degrees,  Fah- 
renheit, and  then  may  be  put  into  the  pots  for  crystalliza- 
tion. These  usually  contain  six  to  eight  gallons.  In  turning 
It  'nto  these,  masses  of  the  crystals  will  be  found,  already, 
at  the  bottom  and  sides  of  the  vessel.  If  the  sirup  is  good, 
some  attention  is  necessary  in  this  operation,  that  the  sirup 
should  not  be  left  to  get  too  cold,  before  it  is  turned  into 
die  pots  ;  as  this  would,  in  some  degree,  impede  the  crys- 
tallization. These  should  be  kept  in  a  close  room,  and  at  a 
steady  temperature.  The  pots  are  of  a  conical  form,  with 
a  hole  in  the  bottom,  which  is  stopped  with  a  cork  or  clay. 
Thirty-six  or  forty  hours  after  the  sirup  has  remained  in 


MANUFACTURE  OF  BEET   SUGAR.  347 

them,  and  when  the  temperature  is  reduced  to  seventy- 
seven  degrees,  Fahrenheit,  or  thereabout,  the  cork  is  re- 
moved, and  the  point  of  the  cone  placed  over  a  vessel  into 
which  the  molasses  (which  begins  immediately  to  run)  is 
received.  In  about  fifteen  days,  in  a  temperature  of  from 
sixty  to  sixty-five  degrees,  Fahrenheit,  they  have  furnished 
above  two  thirds  of  their  molasses.  In  this  degree  of  heat 
L  e  ichole  of  the  molasses  will  not  separate  from  the  sugar  ; 
the  pots  are  therefore  removed  to  another  room,  where  the 
temperature  is  kept  at  from  one  hundred  and  twenty  to  one 
hundred  and  forty  degrees,  Fahrenheit.  There  they  are 
again  placed  over  the  recipients  ;  but,  before  doing. this,  a 
rod  is.  thrust  through  the  hole  in  the  point  of  the  cone,  to 
break  the  incrustation  of  sugar  within,  and  facilitate  the 
draining  of  the  molasses.  After  remaining  here  fifteen 
days,  the  sugar  must  be  completely  freed  from  the  molas- 
ses, and  must  now  be  taken  out.  For  this  purpose,  the 
cone  is  placed  on  its  base,  shook  against  the  platform  on 
which  it  stands,  and,  in  an  hour  or  so,  the  sugar  is  de- 
tached in  the  form  of  the  cone  ;  the  point  of  this  is  im- 
pregnated with  molasses,  and  is  to  be  removed.  It  makes 
an  inferior  sort  of  brown  sugar.  The  rest  of  the  product 
will  be  generally  fine,  light  colored  sugar,  which  is  found 
to  produce  a  larger  proportion  of  refined  sugar  to  the 
weight,  than  any  made  from  the  cane,  and  is,  therefore, 
much  preferred  by  refiners.  The  sugar  made  at  the  be- 
ginning of  the  season  is  easier  made,  and  better  than  that 
made  later. 

The  molasses  collected  in  the  process  of  crystallization, 
is  reboiled,  and  subjected  to  the  same  process  as  the  sir- 
up, and  a  certam  portion  of  sugar  is  the  result ;  the  re- 
siduum is  used  for  many  purposes,  and  is  especially  use- 
ful for  cattle. 

For  further  particulars,  see  the  w'ork  cited  ;  also,  a  man- 
ual translated  from  portions  of  the  treatise  of  M.  M. 
Blachette,  Zoega,  and  J.  De  Fontenelle,  and  published 
by  Marsh,  Capen,  Lyon,  and  Webb,  and  a  more  recent 
work,  on  the  same  subject,  by  David  Lee  Child. 


348  APPENDIX. 


VIII. — Voltaic  Electrical  Engraving. 

The  following  account  of  the  process  of  engraving  in 
relief,  upon  copper-plates,  by  means  of  voltaic  electricity, 
is  from  the  London  Atheneum,  for  October  27,  1839. 
A  previous  number  of  this  paper  contained  a  letter  from 
M.  Jacobi,  detailing  his  experiments  on  the  subject ;  and 
it  appears  that  Mr.  Thomas  Spencer,  of  Liverpool,  had 
also  devoted  much  attention  to  the  subject,  and  had  noi 
only  succeeded  in  doing  all  that  M.  Jacobi  had  done,  but 
had  surmounted  difficulties  which  M.  Jacobi  could  not. 
Mr.  Spencer  proposes,  by  means  of  voltaic  electricitv, 
"  to  engrave  in  rehef  upon  a  plate  of  copper  ;  deposit  a 
voltaic  copper-plate,  having  the  lines  in  relief;  obtain  a 
facsimile  of  a  medal,  reverse  or  obverse,  or  of  a  bronze' 
cast  ;  to  obtain  voltaic  impression  from  plaster,  or  clay  , 
and  to  multiply  the  number  of  already-engraved  copper- 
plates." The  results  which  he  has  already  obtained  are 
said  to  be  very  beautiful. 

Take  a  plate  of  copper,  such  as  is  used  by  an  engrav- 
er ;  solder  a  piece  of  copper  wire  to  the  back  part  of  it, 
and  then  give  it  a  coat  of  wax;  (this  is  best  done  by  heat- 
ing the  plate,  as  well  as  the  wax  ;)  then  write  or  draw  the 
design  on  the  wax,  with  a  black  lead  pencil,  or  a  point. 
The  wax  must  now  be  cut  through  with  a  graver,  or  steel 
point,  taking  special  care  that  the  copper  is  thoroughly 
exposed,  in  every  line.  The  shape  of  the  tool  or  graver 
employed  must  be  such,  that  the  lines  made  are  not  V- 
shape,  but,  as  nearly  as  possible,  with  parallel  sides.  The 
plate  should  next  be  immersed  in  dilute  nitric  acid  ;  say 
three  parts  water  to  one  of  acid.  It  will  at  once  be  seen 
whether  it  is  strong  enough,  by  the  green  color  of  the  so- 
lution, and  the  bubbles  of  nitrous  gas  evolved  from  the 
copper.  Let  the  plate  remain  in  it  long  enough  for  the 
exposed  lines  to  get  slightly  corroded,  so  that  any  minute 
portions  of  wax,  which  might  remain,  may  be  removed. 
The  plate,  thus  prepared,  is  placed  in  a  trough,  separat- 
ed into  two  divisions  by  a  porous  partition  of  plaster  of 
Paris,  or  earthenware  ;  the  one  division  being  filled  with 
a  saturated  solution  of  sulphate  of  copper,  and  the  othei 


VOLTAIC  ELECTRICAL   ENGRAVING.  349 

with  a  saline,  or  acid,  solution.  The  plate  to  be  engrav- 
ed is  placed  in  the  division  containing  the  solution  of  the 
sulphate  of  copper,  and  a  plate  of  zinc,  of  equal  size,  is 
placed  in  the  other  division.  A  metallic  connection  is 
.hen  made  between  the  copper  and  zinc  plates,  by  means 
of  the  copper  wire  soldered  to  the  former  ;  and  the  vol- 
taic circle  is  thus  completed.  The  apparatus  is  then  left 
for  some  days.  As  the  zinc  dissolves,  metalhc  copper 
is  precipitate  J,  from  the  solution  of  the  sulphate  on  the 
copper-plate,  wherever  the  wax  has  been  removed  by 
the  engraving  tool.  After  the  vohaic  copper  has  l^en 
deposited  in  the  lines  engraved  in  the  wax,  the  surface 
of  it  will  be  found  to  be  more  or  less  rough,  according  to 
the  quickness  of  the  action.  To  remedy  this,  rub  the 
surface  with  a  piece  of  smooth  flag,  or  pumice-stone,  with 
water.  Then  heat  the  plate,  and  wash  off  the  wax 
ground,  with  spirits  of  turpentine  and  a  brush.  The 
plate  is  now  ready  to  be  printed  from,  at  an  ordinary 
press. 

In  this  process,  care  must  be  taken  that  the  surface  of 
the  copper  in  the  lines  be  perfectly  clean,  as  otherwise, 
the  deposited  copper  will  not  adhere  with  any  force,  but 
is  easily  detached  w^hen  the  wax  is  removed.  It  is  in 
order  to  insure  this  perfect  cleanness  of  the  copper,  that 
it  is  immersed  in  dilute  nitric  acid.  Another  cause  of 
imperfect  adhesion  of  the  deposited  copper,  which  Mr. 
Spencer  has  pointed  out,  is  the  presence  of  a  minute 
portion  of  some  other  metal,  such  as  lead,  which,  by  be- 
ing precipitated  before  the  copper,  forms  a  thin  film, 
which  prevents  the  adhesion  of  the  subsequently  deposit- 
ed copper.  This  circumstance  may,  however,  be  turn- 
ed to  advantage,  in  some  of  the  other  applications  of 
Mr.  Spencer's  process,  where  it  is  desirable  to  prevent 
the  adhesion  of  the  deposited  copper. 

In  copying  a  coin,  or  medal,  Mr.  Spencer  describes 
two  methods.  The  one  is  by  depositing  voltaic  copper  on 
the  surface  of  the  medal,  and  thus  forming  a  mould,  from 
which,  facsimiles  of  the  original  medal  may  readily  be  ob- 
tained, by  precipitating  copper  into  it.  The  other  is 
even  more  pxpeditious.  Two  pieces  of  clean  milled 
II.  30  XII. 


350  APPENDIX. 

sheet  lead  are  taken,  and  the  medal  being  placed  between 
them,  the  whole  is  subjected  to  pressure  in  a  screw-press, 
and  a  complete  mould,  of  both  sides,  is  thus  formed  in  . 
the  lead,  showing  the  most  delicate  lines,  (in  reverse.) 
Twenty,  or  even  a  hundred,  of  these,  may  be  so  formed 
on  a  sheet  of  lead,  and  the  copper  deposited  by  the  vol- 
taic process,  with  the  greatest  facility.  Those  portions 
of  the  surface  of  the  lead,  which  are  between  the  moulds, 
may  be  varnished,  to  prevent  the  deposition  of  the  lead, 
or,  a  whole  sheet  of  voltaic  copper  having  been  deposi- 
teci^  the  medals  may  afterwards  be  cut  out.  When  cop- 
per is  to  be  deposited  on  a  copper  mould,  or  medal,  care 
must  be  taken  to  prevent  the  metal  deposited  adhering. 
This  Mr.  Spencer  effects  by  heating  the  medal,  and 
rubbing  a  small  portion  of  wax  over  it.  This  wax  is  then 
wiped  off,  a  sufficient  portion  always  remaining  to  pre- 
vent adhesion. 

Enough  has  been  said,  to  enable  any  one  to  repeat, 
and  follow  up,  Mr.  Spencer's  interesting  experiments. 
The  variations,  modifications,  and  adaptations,  of  them, 
are  endless  ;  and  many  new  ones  will  naturally  suggest 
themselves  to  every  scientific  reader. 

IX. — Photogenic  Drawing. 

Some  account  of  Photography,  or  Photogenic  drawing 
has  been  introduced  in  the  previous  pages  of  this  work 
The  following  article,  containing  a  description  of  the  pro- 
cess, is  from  a  work  on  this  subject,  published  by  M.  Da- 
guerre,  and  translated  by  Mr.  Memos,  in  1839. 

The  designs  are  executed  upon  thin  plates  of  silver, 
plated  on  copper.  Although  the  copper  serves  princi- 
pally to  support  the  silver  foil,  the  combination  of  the  two 
metals  tends  to  the  perfection  of  the  effect.  The  silver 
must  be  the  purest  that  can  be  procured.  As  to  the  cop- 
per, its  thickness  ought  to  be  sufficient  to  maintain  the 
perfect  smoothness  and  flatness  of  the  plate,  so  that  the 
images  may  not  be  distorted  by  the  warping  of  the  tablet; 
but  unnecessary  thickness,  beyond  this,  is  to  be  avoided, 
on  account  of  the  weight.  The  thickness  of  the  two 
metals  united  ought  not  to  exceed  that  of  a  stout  card 


PHOTOGENIC   DRAWING.  351 

The  process  is  divided  into  five  operations. 

1.  The  first  consists  in  polishing  and  cleaning  the 
plate,  in  order  to  prepare  it  for  receiving  the  sensitive 
coating,  upon  which  the  light  traces  the  design. 

2.  The  second  is  to  apply  this  coating. 

3.  The  third  is  the  placing  the  prepared  plate,  proper- 
ly, in  the  camera  obscura,  to  the  action  of  hght,  for  the 
purpose  of  receiving  the  image  of  Nature. 

4.  The  fourth  brings  out  this  image,  which,  at  first,  is 
not  visible,  on  the  plate  being  withdrawn  from  the  camera 
obscura. 

5.  The  fifth,  and  last,  operation  has,  for  its  object,  to 
remove  the  sensitive  coating  on  w^hich  the  design  is  first 
impressed,  because  this  coating  would  continue  to  be  af- 
fected by  the  rays  of  light,  a  property  w^hich  would  ne- 
cessarily and  quickly  destroy  the  picture. 

First  Operation. — Preparing  the  Plate. 

The  requisites, for  this  operation,  are, 

A  small  phial  containing  olive  oil. 

Some  very  finely-carded  cotton. 

A  small  quantity  of  very  fine  pumice  powder,  ground 
with  the  utmost  care,  tied  up  in  a  bag  of  muslin,  suffi- 
ciently thin  to  allow  the  powder  to  pass  through,  when  the 
bag  is  shaken. 

A  phial  of  nitric  acid,  diluted  with  water,  in  the  pro- 
portion of  one  pint  of  acid,  to  sixteen  pints  of  distilled 
water.      These  proportions  express  volume,  not  weight. 

A  frame  of  iron  wire,  upon  which  to  place  the  plate, 
in  order  that  it  may  be  heated  by  means  of  a  spirit-lamp. 

Lastly,  a  small  spirit-lamp. 

As  already  stated,  these  photographic  delineations  are 
executed  upon  silver,  plated  on  copper.  The  size  of  the 
plate  will  depend,  of  course,  on  the  dimensions  of  the 
camera.  We  must  begin,  by  polishing  it  carefully.  To 
accomplish  this,  the  surface  of  the  silver  is  powdered  all 
over  with  the  pumice,  by  shaking  the  bag,  without  touch- 
*ng  the  plate. 

Next,  with  some  cotton  dipped  in  a  little  olive  oil,  the 
operator  rubs  die  plate  gently,  rounding  his  strokes.    Dur- 


352  APPENDIX. 

« 

ing  this  operation,  the  plate  must  be  laid  flat  upon  several 
folds  of  paper,  care  being  taken  to  renew  these,  from  time 
to  time,  that  the  tablet  be  not  twisted  from  any  inequality 
in  the  support. 

The  pumice  must  be  renewed,  and  the  cotton  changed^ 
several  times.  The  mortar,  employed  for  preparing  the 
pumice,  must  be  of  porphyry.  The  powder  is  afterwards 
finished,  by  grinding  upon  polished  glass  with  a  glass 
muller,  and  very  pure  water.  And  lastly,  it  must  be 
perfectly  dried.  It  will  be  readily  apprehended,  of  what 
importance  it  is  to  attend  to  these  directions,  since  upon 
the  high  polish  of  the  silver,  depends,  in  a  great  measure, 
the  beauty  of  the  future  design.  When  the  plate  is  well 
polished,  it  must  next  be  cleaned,  by  powdering  it  all 
over,  once  more,  with  pumice,  and  rubbing  with  dry  cot- 
ton, always  rounding  and  crossing  the  strokes,  for  it  is 
impossible  to  obtain  a  true  surface  by  any  other  motion 
of  the  hand.  A  little  pledget  of  cotton  is  now  rolled  up, 
and  moistened  with  the  diluted  acid  already  mentioned, 
by  applying  the  cotton  to  the  mouth  of  the  phial,  and  in- 
verting it,  pressing  gently,  so  that  the  centre  only  of  the 
cotton  may  be  wetted,  and  but  slightly,  care  being  taken, 
not  to  allow  any  acid  to  touch  the  fingers.  The  surface 
of  the  plate  is  now  rubbed  equally,  all  over,  with  the 
acid,  applied  by  the  pledget  of  cotton.  Change  the  cot- 
ton, and  keep  rubbing,  rounding  as  before,  that  the  acid 
may  be  equally  spread,  yet  in  so  small  a  quantity,  as  just 
to  skim  the  surface,  so  to  speak.  If,  as  frequently  hap- 
pens, the  acid  run  into  small  drops,  from  the  high  polish, 
change  the  cotton  repeatedly,  and  break  down  the  glob- 
ules as  quickly  as  possible,  but  always  by  gently  rubbing, 
for  if  allowed  to  rest,  or  to  run  upon  the  plate,  they  will 
leave  stains.  It  will  be  seen  when  the  acid  has  been 
properly  diffused,  from  the  appearance  of  a  thin  veil, 
spread  regularly  over  the  whole  surface  of  the  plate.  Once 
more  powder  over  pumice,  and  clean  it  with  fresh  cotton, 
rubbing  as  before,  but  very  slightly. 

The  plate  is  now  to  be  subjected  to  a  strong  heat.  It 
is  placed  upon  the  wire  frame,  the  silver  upwards.  The 
spirit-lamp  is  applied  below  the  hand,  moving  it  round. 


PHOTOGENIC  DRAWING.  353 

the  flame  touching  and  playing  upon  the  copper.  This 
operation  being  continued  at  least  five  minutes,  a  white 
strong  coating  is  formed  all  over  the  surface  of  the  silver, 
if  the  lamp  has  been  made  to  traverse  with  proper  regu- 
larity. The  lamp  is  now  withdrawn.  A  fire  of  charcoal 
may  be  used  instead  of  the  lamp,  and  is,  perhaps,  prefera- 
ble, the  operation  being  sooner  completed.  In  this  latter 
case,  the  wire  frame  is  unnecessary,  because  the  plate 
may  be  held  by  one  corner  with  pincers,  and  so  held  over 
the  fire,  moving  it  at  the  same  time,  till  all  is  equally  heat- 
ed, and  the  veil  appear,  as  before  described. 

The  plate  is  now  to  be  cooled,  suddenly^  by  placing  it 
on  a  cold  substance,  such  as  a  mass  of  metal,  or  stone,  or, 
best  of  all,  a  marble  table.  When  perfectly  cold,  it  is  to 
be  again  polished,  an  operation  speedily  performed,  since 
the  gummy  appearance  merely  has  to  be  removed,  which 
is  done  by  the  dry  pumice  and  cotton,  repeated  several 
times,  changing  the  cotton  frequently.  The  polishing 
being  thus  completed,  the  operation  of  the  acid  is  to  be 
repeated  three  diiferent  times,  dry  pumice  being  powder- 
ed over  the  plate,  each  time,  and  polished  off  very  gen- 
tly with  the  cotton,  which  must  be  very  clean,  care  being 
taken  not  to  breathe  upon  the  plate,  or  to  touch  it  with  the 
fingers,  or  even  with  the  cotton  upon  which  the  fingers 
have  rested  ;  for  the  slightest  stain  upon  the  surface  will 
be  a  defect  in  the  drawing. 

When  the  plate  is  not  intended  for  immediate  use,  the 
last  operation  of  the  acid  is  not  performed.  This  allows 
any  number  of  plates  to  be  kept  prepared,  up  to  the  last 
slight  operation  ;  and  they  may  be  purchased  in  this  state, 
if  required.  It  is,  however,  indispensable,  that  a  last 
operation  by  acid,  as  described,  be  performed  on  every 
plate,  immediately  before  it  be  placed  in  the  camera. 
Lastly,  every  particle  of  dust  is  removed,  by  gently 
cleaning  the  whole  edges,  and  back,  also,  with  cotton. 

Second  Operation. — Coating  the  Plate. 

For  this  operation,  we  require, 

A  box. 

A  small  board. 

30* 


354  APPENDIX. 

Four  small  metallic  bands,  the  same  substance  as  the 

})lates. 

A  small  handle,  and  a  box  of  small  tacks. 

A  phial  of  iodine. 

The  plate  is  first  to  be  fixed  on  the  board,  by  means 
of  the  metallic  bands,  with  their  small  catches  and  tacks. 
The  iodine  is  now  put  into  a  little  dish  at  the  bottom  of 
the  box.  It  is  necessary  to  divide  the  iodine  into  pieces, 
in  order  to  render  the  exhalation  the  more  extensively 
and  more  equally  diffused  ;  otherwise,  it  would  form  cir- 
cles in  the  centre  of  the  plate,  which  would  destroy  this 
essential  requisite.  The  board  is  now  fitted  into  its  po- 
sition, the  plate  face  downwards,  the  whole  being  support- 
ed by  small  brackets  projecting  from  the  four  corners  of 
the  box,  the  lid  of  which  is  then  closed.  In  this  posi- 
tion, the  apparatus  remains  till  the  vaporization  of  the 
iodine,  which  is  condensed  upon  the  plate,  has  covered 
its  surface  with  a  fine  coating  of  a  yellow  gold  color.  If 
this  operation  be  protracted,  the  gold  color  passes  into 
violet,  which  must  be  avoided  ;  because  in  this  state  the 
coating  is  not  so  sensitive  to  the  impressions  of  hght. 
On  the  contrary,  if  the  coating  be  too  pale,  the  image  of 
\ature  in  the  camera  will  be  too  faint  to  produce  a  good 
picture.  A  decided  gold  color, — nothing  more,  nothing 
less, — is  the  only  assurance  that  the  ground  of  the  future 
picture  is  duly  prepared.  The  time  for  this  cannot  be 
determined,  because  it  depends  on  several  circumstances. 
Of  these,  the  two  principal  are  the  temperature  of  the 
apartment,  and  the  state  of  the  apparatus.  The  opera- 
tion should  be  left  entirely  to  spontaneous  evaporation  of 
the  iodine  ;  or,  at  all  events,  no  other  heat  should  be  used, 
than  what  can  be  applied  through  the  temperature  of  the 
room,  in  which  the  operation  takes  place.  It  is  also  very 
important,  that  the  temperature  of  the  inside  of  the  box 
be  equal  to  that  of  the  air  outside  ;  for,  otherwise,  a  depo- 
sition of  moisture  takes  place  upon  the  plate,  a  circum- 
stance most  injurious  to  the  final  result.  Secondly,  as 
respects  the  state  of  the  apparatus  ;  the  oftener  it  has 
been  used,  the  less  time  is  required,  because,  in  this  case, 
the  interior  of  the  box  being  penetrated  with  the  vapors 


PHOTOGENIC  DRAWING.  355 

of  iodine,  these  arise  from  all  sides,  condensing  thus  more 
equally  and  more  rapidly  upon  the  surface  of  the  plate  ;  a 
very  important  advantage.  Hence,  it  is  of  consequence 
to  leave  always  a  small  quantity  of  iodine  in  the  cup,  and 
to  protect  this  latter  from  damp.  Hence,  likewise,  it  is 
obvious,  that  an  apparatus  of  this  kind,  which  has  been 
some  time  in  use,  is  preferable  to  a  new  box  ;  for,  in 
the  former,  the  operation  is  always  more  expeditiously 
performed. 

Since,  from  these  causes,  the  time  cannot  be  fixed,  a 
priori,  and  may  vary  from  five  minutes  to  half  an  hour, 
rarely  more,  unless  the  weather  be  too  cold,  means  must 
be  adopted  for  examining  the  plate,  from  time  to  time. 
In  these  examinations,  it  is  important  not  to  allow  the 
fight  to  fall  directly  upon  the  plate.  Also,  if  it  appear 
that  the  color  is  deeper  on  one  side  of  the  plate  than  the 
other,  to  equalize  the  coating,  the  board  must  be  re- 
placed, not  exactly  in  its  former  position,  but  turned  one 
quarter  round,  at  each  inspection.  In  order  to  accom- 
plish these  repeated  examinations,  without  injuring  the 
sensibility  of  the  ground,  or  coating,  the  process  must  be 
conducted  in  a  darkened  apartment,  into  which  the  light 
is  admitted  sideways,  never  from  the  roof ;  the  door  left 
a  little  ajar  answers  best.  When  the  operator  would 
inspect  the  plate,  he  raises  the  lid  of  the  box,  and,  lifting 
the  board  with  both  hands,  turns  up  the  plate  quickly, 
and  very  fittle  fight  suffices  to  show  him  the  true  color 
of  the  coating.  If  too  pale,  the  plate  must  be  instantly 
replaced,  till  it  attain  the  proper  gold  tone  ;  but  if  this 
tint  be  passed,  the  coating  is  useless,  and  the  operations 
must  be  repeated  from  the  commencement  of  the  first. 

From  description,  this  operation  may,  perhaps,  seem 
difficult  ;  but  with  a  little  ])ractice,  one  comes  to  know, 
pretty  nearly,  the  precise  interval  necessary  to  produce 
the  true  tone  of  color,  and  also  to  inspect  the  plate  with 
great  rapidity,  so  as  not  to  allow  time  for  the  light  to  act. 

When  the  coating  has  reached  the  proper  tone  of  yel- 
low, the  plate,  with  the  board  to  w^hich  it  is  fixed,  is  slip- 
ped into  the  frame,  and  thus  adjusted,  at  once,  in  the  ca- 
mera.    In  this  transference,  care  must  be  taken  to  protect 


356  APPENDIX. 

the  plate  from  the  light.  A  taper  should  be  used  ;  and 
even  with  this  precaution,  the  operation  ought  to  be  per- 
formed as  quickly  as  possible,  for  a  taper  will  leave  traces 
of  its  action,  if  continued  for  any  length  of  time. 

We  pass  now  to  the  third  operation,  that  of  the  ca 
mera.  If  possible,  the  one  should  immediately  succeed 
the  other  ;  the  longest  interval  between  the  second  and 
third  ought  not  to  exceed  an  hour.  Beyond  this  space, 
the  action  of  the  iodine  and  silver  no  longer  possesses  the 
requisite  photogenic  properties. 

Observanda. — Before  making  use  of  the  box,  the  oper- 
ator should  clean  it  thoroughly,  turning  it  bottom  upwards, 
in  order  to  empty  it  of  all  the  particles  of  iodine  which 
may  have  escaped  from  the  cup,  avoiding,  at  the  same 
time,  touching  the  iodine  with  the  fingers.  During  the 
operation  of  coating,  the  cup  ought  to  be  covered  with  a 
piece  of  gauze  stretched  on  a  ring.  The  gauze  regulates 
the  evaporation  of  the  iodine,  and  also  prevents  the  com- 
pression of  the  air,  on  the  lid  being  shut,  from  scattering 
the  particles  of  iodine,  some  of  which,  reaching  the  plate, 
would  leave  large  stains  on  the  coating.  For  the  same 
reason,  the  top  should  always  be  let  down  with  the  great- 
est gentleness,  not  to  raise  the  dust  in  the  inside,  the  par- 
ticles of  which,  being  charged  with  the  vapor  of  the  io 
dine,  would  certainly  reach  and  damage  the  plate. 

Third  Operation. —  The  Camera. 

The  apparatus,  required  in  this  operation,  is  limited  tt 
the  camera  obscura. 

This  third  operation  is  that,  in  which,  by  means  ol 
light,  acting  through  the  camera.  Nature  impresses  an 
image  of  herself  on  the  photographic  plate,  enlightened 
by  the  sun,  for  then  the  operation  is  more  speedy.  It 
is  easy  to  conceive  that  this  operation,  being  accom- 
plished only  through  the  agency  of  light,  will  be  the  more 
rapid  in  proportion  as  the  objects,  whose  photographic 
images  are  to  be  delineated,  stand  exposed  to  a  strong 
illumination,  or  in  their  own  nature  present  bright  lines, 
and  surfaces. 

After  having  placed  the  camera  in  front  of  the  land 


PHOTOGENIC   DRAWING.  357 

scape,  or  facing  any  other  object  of  which  it  may  be  desi- 
rable to  obtain  a  representation,  the  first  essential  is  a  per- 
fect adjustment  of  the  focus,  that  is  to  say,  making  your 
arrangements,  so  as  to  obtain  the  oudines  of  the  subject 
with  great  neatness.  This  is  accomplished,  by  advancing 
or  withdrawing  the  frame  of  the  obscured  glass,  which  re- 
ceives the  images  of  natural  objects.  The  adjustment 
being  made  with' satisfactory  precision,  the  movable  part 
of  the  camera  is  fixed  by  the  proper  means,  and  the  ob- 
scured glass  being  withdrawn,  its  place  is  supplied  by  the 
apparatus,  with  the  plate  attached,  as  already  described, 
and  the  whole  secured  by  small  brass  screws.  The  light 
is,  of  course,  all  this  time  excluded  by  the  inner  doors. 
These  are  now  opened,  by  means  of  two  semicircles,  and 
the  plate  is  disposed,  ready  to  receive  its  proper  impres- 
sions. It  remains  only  to  open  the  aperture  of  the  ca- 
mera, and  to  consult  a  watch. 

This  latter  is  a  task  of  some  nicety,  inasmuch  as  noth- 
ing is  visible,  and  it  is  quite  impossible  to  determine 
the  time  necessary  for  producing  a  design,  this  depending 
entirely  on  the  intensity  of  the  light  on  the  objects,  the 
imagery  of  which  is  to  be  reproduced.  At  Paris,  for  ex- 
ample, this  varies  from  three  to  thirty  minutes. 

It  is  likewise  to  be  remarked,  that  the  seasons,  as  well 
as  the  hour  of  the  day,  exert  considerable  influence  on 
the  celerity  of  the  operation.  The  most  favorable  lime 
is  from  seven  to  three  o'clock  ;  and  a  drawing  which,  in 
the  months  of  June  and  July,  at  Paris,  may  be  taken  in 
three  or  four  minutes,  will  require  five  or  six,  in  May  or 
August ;  seven  or  eight,  in  April  and  September ;  and  so 
on,  in  proportion  to  the  progress  of  the  season.  These 
are  only  general  data  for  very  bright,  or  strongly  illumin- 
ated, objects  ;  for  it  often  happens,  that  twenty  minutes 
are  necessary,  in  the  most  favorable  months,  when  the 
objects  are  entirely  in  shadow. 

After  what  has  just  been  said,  it  will  readily  occur  to 
the  reader,  that  it  is  impossible  to  specify,  with  precision, 
the  exact  length  of  time  necessary  to  obtain  photographic 
designs.  Practice  is  the  only  sure  guide  ;  and,  with  this 
advantage,  one  soon   comes  to  appreciate  the  required 


358  APPENDIX. 

time,  very  correctly.  The  latitude  is,  of  course,  a  fixed 
element  in  this  calculation.  In  the  south  of  France,  for 
example,  and  generally  in  all  those  countries,  in  which 
light  has  great  intensity,  as  Spain,  Italy,  &c.,  we  can 
easily  understand  that  these  designs  must  be  obtained  with 
greater,  promptitude,  than  in  more  northern  regions.  It 
is,  however,  very  important,  not  to  exceed  the  time  nec- 
essary, in  different  circumstances,  for  producing  a  design  ; 
because,  in  that  case,  the  lights  in  the  drawing  will  not  be 
clear,  but  will  be  blackened  by  a  too-prolonged  solariza- 
tion.  If,  on  the  contrary,  the  time  has  been  too  short,  the 
sketch  will  be  very  vague,  and  without  the  proper  details. 

Supposing  that  he  has  failed  in  a  first  trial,  by  with- 
drawing the  tablet  too  soon,  or  by  leaving  it  too  long  ex- 
posed, the  operator,  in  either  case,  should  commence 
with  another  plate  immediately  ;  the  second  trial,  being 
corrected  by  the  first,  almost  insures  success.  It  is  even 
useful,  in  order  to  acquire  experience,  to  make  some  es- 
says of  this  kind. 

In  this  stage  of  the  process,  it  is  the  same  as  for  the 
coating  ;  we  must  hasten  to  the  next  operation.  When 
the  plate  is  withdrawn  from  the  camera,  it  should  imme- 
diately be  subjected  to  the  subsequent  process  ;  there 
ought,  at  most,  not  to  be  a  longer  interval  than  an  hour, 
between  the  third  and  fourth  operations  ;  but  one  is  al- 
ways surest  of  disengaging  the  images,  when  no  space 
has  been  allowed  to  intervene. 

Fourth  Operation. — Mercurialj  or  Disengaging,  Process. 

Here  are  required,  a  phial  of  mercury,  containing  at 
least  three  ounces. 

A  lamp,  with  spirit  of  wine. 

An  iron  vessel,  prepared  with  apparatus  for  receiving 
he  plate,  and  submitting  it  to  the  vapor  of  mercury. 

A  glass  funnel  with  a  long  neck. 

By  means  of  the  funnel,  the  mercury  is  poured  into 
the  cup,  at  the  bottom  of  the  larger  vessel.  The  quan- 
tity must  be  sufficient  to  cover  the  bulb  of  a  thermome- 
ter. Afterwards,  and  throughout  the  remaining  opera- 
nons,  no  light,  save  a  taper,  can  be  used. 


PHOTOGENIC  DRAWING.  iibi 

The  board,  with  the  plate  affixed,  is  now  to  be  with- 
drawn from  the  frame  already  described,  as  adapted  to 
the  camera.  The  board  and  plate  are  placed  within  the 
ledges  of  the  black  iron  vessel,  at  an  angle  of  forty-fire 
degrees,  the  tablet  with  sketch  downwards,  so  that  it  can 
be  seen  through  the  glass.  The  top  is  then  gently  put 
down,  so  as  not  to  raise  up  particles  of  the  mercury. 

When  all  things  are  thus  disposed,  the  spirit  lamp  is 
lighted,  and  placed  under  the  cup  containing  mercury. 
The  operation  of  the  lamp  is  allowed  to  continue  till  the 
thermometer,  the  bulb  of  which  is  covered  by  the  mer- 
cury, indicates  a  temperature  of  sixty  degrees  centigrade, 
[140°,  Fahrenheit.]  The  lamp  is  then  immediately  with- 
drawn. If  the  thermometer  has  risen  rapidly,  it  will  con- 
tinue to  rise  without  the  aid  of  the  lamp  ;  but  this  elevation 
ought  not  to  exceed  seventy-five  degrees  centigrade,  [167° 
Fahrenheit.] 

The  impress  of  the  image  of  Nature  existy  upon  the 
plate,  but  it  is  invisible.  It  is  not  till  after  the  lapse  cf 
several  minutes,  that  the  faint  tracery  of  objects  begins  to 
appear,  of  which  the  operator  assures  himself,  by  looking 
through  the  glass,  by  the  light  of  a  taper,  using  it  cau- 
tiously, that  its  rays  may  not  fall  upon,  and  injure,  the  nas- 
cent images  of  the  sketch.  The  operation  is  continued 
till  the  thermometer  sink  to  forty-five  degrees  centigrade, 
[113°,  Fahrenheit;]  the  plate  is  then  withdrawn,  and  this 
operation  completed. 

When  the  objects  have  been  strongly  illuminated,  or 
when  the  action  in  the  camera  has  been  continued  rather 
too  long,  it  happens  that  this  fourth  operation  is  completed 
before  the  thermometer  has  fallen  even  to  fifty-five  degrees 
centigrade.  One  may  always  know  this,  however,  by  ob- 
serving the  sketch  through  the  glass. 

It;  is  necessary,  after  each  operation,  to  clean  the  inside 
of  the  apparatus  carefully,  to  remove  the  slight  coating  of 
mercury  adhering  to  it.  When  the  apparatus  has  to  be 
packed,  for  the  purpose  of  removal,  the  mercury  is  with- 
drawn by  a  small  cock,  inclining  the  vessel  to  that  side. 

One  may  now  examine  the  sketch,  by  a  feeble  light,  in 
order  to  be  certain  that  the  processes  hitherto  have  sue- 


360  APPENDIX. 

ceeded.  The  plate  is  now  detached  from  the  board,  and 
the  little  bands  of  metal,  which  held  it  there,  are  carefully 
cleaned  with  pumice  and  water,  after  each  experiment  ; 
a  precaution  rendered  necessary  from  the  coating  both  of 
iodine  and  mercury,  which  they  have  acquired.  The  plate 
is  now  deposited  in  the  grooved  box,  until  it  undergoes  the 
fifth  and  last  operation.  This  may  be  deferred,  if  not  con- 
venient ;  for  the  sketch  may  now  be  kept  for  months,  in 
its  present  state,  without  alteration,  provided  it  be  not  too 
frequently  inspected  by  the  full  daylight. 

Fifth  Operation. — Fixing  the  Impression. 

The  object  of  this  final  process,  is  to  remove  from  the 
tablet  the  coating  of  iodine,  which,  continuing  to  decom- 
pose by  light,  would  otherwise  speedily  destroy  the  de- 
sign, when  too  long  exposed.  For  this  operation,  the  re- 
quisites are, 

A  saturated  solution  of  common  salt,  or  a  weak  solu- 
tion of  hyposulphite  of  pure  soda. 

An  apparatus  of  japanned  white  iron,  for  washing  the 
designs. 

Two  square  troughs,  of  sheet  copper. 

A  vessel  for  distilled  w^ater. 

In  order  to  remove  the  coating  of  iodine,  common  salt 
is  put  into  a  bottle,  with  a  wide  mouth,  which  is  filled 
one  fourth  with  salt  and  three  fourths  with  pure  water. 
To  dissolve  the  salt,  shake  the  bottle,  and,  when  the 
whole  forms  a  saturated  solution,  filter  through  paper. 
This  solution  is  prepared  in  large  quantities,  beforehand, 
and  kept  in  corked  bottles.  « 

Into  one  of  the  square  troughs,  pour  the  solution,  filling 
it  to  the  height  of  an  inch  ;  into  the  other,  pour,  in  like 
manner,  your  water.  The  solution  of  salt  may  be  re- 
placed by  one  of  hyposulphite  of  soda,  which  is  even 
preferable,  because  it  removes  the  iodine  entirely,  which 
the  saline  solution  does  not  always  accomplish,  especially 
when  the  sketches  have  been  laid  aside  for  some  time,  be- 
tween the  fourth  and  fifth  operations.  It  does  not  require 
to  be  warmed,  and  a  less  quantity  is  required. 

First,  the  plate  is  placed  in  common  water,  poured  into 


PHOTOGENIC  DRAWING.  361 

a  trough,  plunging  and  withdrawing  it  immediately,  the 
surface  merely  requiring  to  be  moistened  ;  then  plunge  it 
into  the  saline  solution,  which  latter  would  act  upon  the 
drawing,  if  not  previously  hardened  by  the  washing  in 
pure  water.  To  assist  the  effect  of  the  sahne  solutions, 
the  plate  is  moved  about  in  them,  by  means  of  a  little  hoop 
of  coppei  wire.  When  the  yellow  color  has  quite  disap- 
peared, the  plate  is  lifted  up  with  both  hands,  care  being 
taken  not  to  touch  the  drawing,  and  plunged  again  into 
the  first  trough  of  pure  water. 

Next,  the  apparatus  and  the  bottle  having  been  previ- 
ously prepared,  made  very  clean,  and  the  bottle  filled  with 
'  distilled  water,  the  plate  is  withdrawn  from  the  trough,  and 
being  instantly  placed  upon  the  inclined  plane,  distilled 
water,  hot,  but  not  boiling,  is  made  to  flow  in  a  stream 
over  its  whole  surface,  carrying  away  every  remaining 
portion  of  the  saline  wash. 

If  hyposulphite  has  been  used,  the  distilled  water  need 
not  be  so  hot,  as  when  common  salt  has  been  em- 
ployed. 

Not  less  than  a  quart  of  distilled  water  is  required, 
when  the  design  is,  in  its  dimensions,  eight  and  a  half  by 
six  and  a  half  inches.  The  drops  of  water,  remaining  on 
the  plate,  must  be  removed  by  forcibly  blowing  upon  it, 
for  otherwise,  in  drying,  they  would  leave  stains  on  the 
drawing.  Hence,  also,  will  appear  the  necessity  of  using 
very  pure  water ;  for  if,  in  this  last  washing,  the  liquid  con- 
tain any  admixture  of  foreign  substances,  they  will  be  de- 
posited on  the  plate,  leaving  behind  numerous  and  per- 
maq^nt  stains.  To  be  assured  of  the  purity  of  the  wa- 
ter, let  a  drop  fall  upon  a  piece  of  polished  metal ; 
evaporate  by  heat,  and  if  no  stain  be  left,  the  water  is 
pure.  Distilled  water  is  always  sufficiently  pure,  without 
this  trial. 

After  this  washing,  the  drawing  is  finished  ;  it  remains 
only  to  preserve  it  from  the  dust,  and  from  the  vapors 
that  might  tarnish  the  silver.  The  mercury,  by  the  ac- 
tion of  which  the  images  are  rendered  visible,  is  par- 
tially decomposed  ;  it  resists  washing,  by  adhesion  to  tho 
silver,  but  cannot  endure  the  slightest  rubbing. 

II.  31    •  XII. 


362  APPENDIX. 

To  preserve  these  sketches,  then,  place  them  in  squaies 
of  strong  pasteboard,  with  a  glass  over  them,  and  frame 
the  whole  in  wood.  They  are  thenceforth  unalterable, 
even  by  the  sun's  light. 

In  travelling,  the  collector  may  preserve  his  sketches 
in  a  box  ;  and,  for  greater  security,  may  close  the  joints 
of  tlie  lid  with  a  collar  of  paper. 

It  is  necessary  to  state,  that  the  same  plate  may  be  em- 
ployed for  several  successive  trials,  provided  the  silver  be 
not  polished  through  to  the  copper.  But  it  is  very  im- 
portant, after  each  trial,  to  remove  the  mercury  immedi- 
ately, by  using  the  pumice  powder  with  oil,  and  changing 
the  cotton  frequently  during  the  operation.  If  this  be 
neglected,  the  mercury  finally  adheres  to  the  silver  ;  and 
fine  drawings  cannot  be  obtained,  if  this  amalgam  be  pres- 
ent. They  always,  in  this  case,  want  firmness,  neatness, 
and  vigor  of  outline,  and  general  effect. 

\ 

A  number  of  experiments,  with  prepared  paper,  have 
been  made  by  different  individuals,  with  various  degrees 
of  success,  in  Great  Britain.  From  among  the  notices 
■)f  these  experiments,  as  they  have  appeared  in  different 
ournals,  the  following  selections  have  been  made. 

In  the  spring  of  1834,  Mr.  Talbot  began  a  series  of 
experiments,  with  the  hope  of  turning  to  useful  account 
the  singular  susceptibility  evinced  by  the  nitrate  of  silver, 
when  exposed  to  the  rays  of  a  powerful  light.  He  says, 
"  In  the  course  of  my  experiments  directed  to  that  end, 
I  have  been  astonished  at  the  variety  of  effects,  whk^  I 
have  found  produced,  by  a  very  limited  number  of  differ- 
ent processes,  when  combined  in  various  ways  ;  and  also, 
at  the  length  of  time,  which  sometimes  elapses,  before 
the  full  effect  of  these  manifests  itself  with  certainty. 
For  I  have  found,  that  images  formed  in  this  manner, 
which  have  appeared  in  good  preservation,  at  the  end  of 
twelve  months  from  their  formation,  have  nevertheless 
somewhat  altered,  during  the  second  year."  He  was  in- 
duced, from  this  circumstance,  to  watch  more  closely  the 
progress  of  this  change,  fearing  that,  in  process  of  time. 


PHOTOGENIC   DRAWING.  363 

all  his  pictures  might  be  found  to  deteriorate.     This,  how 
ever,  was  not  the  case,  and  several  have  withstood  the 
action  of  the  Hght,  for  more  than  five  years. 

The  images,  obtained  by  this  process,  are  themselves 
white,  but  the  ground  is  differently  and  agreeably  color- 
ed ;  and,  by  slightly  varying  the  proportions,  and  some  tri- 
fling details  of  manipulation,  any  of  the  following  colors 
were  readily  obtained ;  light  blue,  yellow,  pink,  brown, 
black,  and  a  dark  green,  nearly  approaching  to  black. 

The  first  objects,  to  which  this  process  was  applied, 
were  leaves  and  flowers,  which  it  rendered  with  extraor- 
dinary fidelity,  representing  even  the  veins  and  minute 
hairs  with  which  they  were  covered,  and  which  were  fre- 
quently imperceptible,  without  the  aid  of  a  microscope. 
Mr.  Talbot  goes  on  to  mention,  that  the  following  con- 
siderations led  him  to  conceive  the  possibility  of  discov- 
ering a  preservative  process.  Nitrate  of  silver,  which 
has  become  darkened  by  exposure  to  the  light,  is  no  lon- 
ger the  same  chemical  substance  as  before  ;  therefore,  if 
chemical  re-agents  be  applied  to  a  picture,  obtained  in  the 
manner  already  mentioned,  the  darkened  parts  will  be 
acted  upon  in  a  different  manner  from  those  which  re- 
tain their  original  color,  and,  after  such  action,  they  will 
probably  be  no  longer  affected  by  the  rays  of  the  sun, 
or,  at  all  events,  will  have  no  tendency  to  assimilate  b} 
such  exposure  ;  and,  if  they  remain  dissimilar,  the  pic- 
ture will  continue  distinct,  and  the  great  difficulty  be  over 
come. 

The  first  trials  of  the  inventor,  to  destroy  the  suscepti- 
bility of  the  metallic  oxide,  were  entirely  abortive  ;  but 
he  has  at  length  succeeded,  to  an  extent  equal  to  his  most 
sanguine  expectations.  The  paper,  employed  by  Mr. 
Talbot,  is  superfine  writing-paper ;  this  is  dipped  into  a 
weak  solution  of  common  salt,  and  dried  with  a  towel, 
till  the  salt  is  evenly  distributed  over  the  surface ;  a  solu- 
tion of  nitrate  of  silver  is  then  laid  over  one  side  of  the 
paper,  and  the  whole  is  dried  by  the  heat  of  the  fire. 
It  is,  however,  necessary  to  ascertain,  by  experiment, 
the  exact  degree  of  strength  requisite  in  both  the  ingredi- 
ents ;  for,  if  the  salt  predominates,  the  sensibility  of  the 


364  APPENDIX. 

paper  gradually  diminishes,  in  proportion  to  this  excess, 
till  the  effect  almost  entirely  disappears. 

In  endeavoring  to  remedy  this  evil,  Mr.  Talbot  discov- 
ered, that  a  renewed  application  of  the  nitrate  not  only 
obviated  the  difficulty,  but  rendered  the  preparation  more 
sensitive  than  ever  ;  and,  by  a  repetition  of  the  same  pro- 
cess, the  mutability  of  the  paper  will  increase  to  such  a 
degree,  as  to  darken  of  itself,  without  exposure  to  the 
light.  This  shows,  that  the  attempt  has  been  carried  too 
far,  and  the  object  of  the  experimentalist  must  be  to  ap- 
proach, without  attaining  this  condition.  Having  prepar- 
ed the  paper,  and  taken  the  sketch,  the  next  object  is,  to 
render  it  permanent,  by  destroying  the  susceptibility  of 
the  ingredients  for  this  purpose.  Mr.  Talbot  tried  am- 
monia, and  several  other  re-agents,  with  little  success,  till 
the  iodine  of  potassium,  greatly  diluted,  gave  the  desired 
result :  this  hquid,  when  applied  to  the  drawing,  produ- 
ced an  iodine  of  silver,  a  substance  insensible  to  the  ac- 
tion of  light.  This  is  the  only  method  of  preserving  the 
picture  in  its  original  tints  ;  but  it  requires  considerable 
'licety,  and  an  easier  mode  is  sufficient  for  ordinary  pur- 
poses. It  consists  in  immersing  the  picture  in  a  strong 
solution  of  salt,  wiping  ofi'  the  superfluous  moisture,  and 
drj^ing  it  by  the  heat  of  the  fire  ;  on  exposure  to  the  sun, 
the  white  parts  become  of  a  pale  lilac,  which  is  per- 
manent and  immovable.  Numerous  experiments  have 
shown  the  inventor,  that  the  depth  of  these  tints  depends 
on  the  strength  of  the  solution  of  sah.  He  also  mentions, 
that  those  prepared  by  iodine  become  a  bright  yellow,  un- 
der the  influence  of  heat,  and  regain  their  original  color ^on 
cooling.  Without  the  application  of  one  of  these  preserv- 
atives, the  image  will  disappear,  by  the  action  of  the  sun  ; 
but,  if  enclosed  in  a  portfoho,  will  be  in  no  danger  of  altera- 
tion :  this,  Mr.  Talbot  remarks,  will  render  it  extremely 
convenient  to  the  traveller,  who  may  take  a  copy  of  any 
object  he  desires,  and  apply  the  preservative  at  his  leisure. 
In  this  respect,  Mr.  Talbot's  system  is  superior  to  that 
of  M.  Daguerre,  since  it  would  be  scarcely  possible  for  a 
traveller  to  burden  himself  with  a  number  of  metallic  plates, 
which,  in  the  latter  process,  are  indispensable. 


PHOTOGENIC  DRAWING.  365 

An  advantage  of  equal  importance  exists  in  the  rapid- 
ity with  which  Mr.  Talbot's  pictures  are  executed ;  for 
which  half  a  second  is  considered  sufficient ;  a  circum- 
stance that  gives  him  a  better  chance  of  success  in  delin- 
eating animals,  or  fohage. — Foreign  Quarterly  Review. 


J^otice  of  a  cheap  and  simple  method  of  preparing  pa- 
per for  Photograpic  Drawings  in  which  the  use  of  any 
salt  of  silver  is  dispensed  with  :  by  Mungo  Ponton, 
Esq.,  F.  R.  S.  E.,  Foreign  Secretary  Society  of  Arts 
for  Scotland.     Communicated  by  the  Society  of  Arts.* 

While  attempting  to  prepare  paper  with  the  chromate 
of  silver,  for  which  purpose  I  used  first  the  chromate  of 
potash,  and  then  the  bichromate  of  that  alkah,  I  discov- 
ered, that,  when  paper  was  immersed  in  the  bichromate 
of  potash  alone,  it  was  powerfully  and  rapidly  acted  on 
b'y  the  sun's  rays.  It  accordingly  occurred  to  me,  to  try 
paper  so  prepared,  to  obtain  drawings,  though  I  did  not 
at  first  see  how  they  were  to  be  fixed.  The  result  ex- 
ceeded my  expectations.  When  an  object  is  laid  in  the 
usual  way  on  this  paper,  the  portion  exposed  to  the  light 
speedily  becomes  tawny,  passing  more  or  less  into  a  deep 
orange,  according  to  the  strength  of  the  solution,  and  the 
intensity  of  the  light.  The  portion  covered  by  the  ob- 
ject retains  the  original  bright  yellow  tint,  which  it  had 
before  exposure,  and  the  object  is  thus  represented  yellow 
upon  an  orange  ground,  there  being  several  gradations  of 
shade,  or  tint,  according  to  the  greater  or  less  degree  of 
traasparency  in  the  difierent  parts  of  the  object. 

In  this  state,  of  course,  the  drawing,  though  very  beau- 
tiful, is  evanescent.  To  fix  it,  all  that  is  required  is 
careful  immersion  in  water,  when  it  will  be  found  that 
those  portions  of  the  salt,  which  have  not  been  acted  on 
by  the  light,  are  readily  dissolved  out,  while  those  which 
have  been  exposed  to  the  light  are  completely  fixed  in 
the  paper.  By  this  second  process,  the  object  is  obtained 
white,  upon  an  orange  ground,  and  quite  permanent.  If 
exposed,  for  many  hours  together,  to  strong  sunshine,  the 

*  Read  before  the  Society  of  Arts  for  Scotland,  29th  May,  1839. 
31* 


366       .  APPENDIX. 

color  of  the  ground  is  apt  to  lose  in  depth,  but  not  moie 
so  than  most  other  coloring  matters. 

The  action  of  light,  on  the  bichromate  of  potash,  dif- 
fers from  that  upon  the  salts  of  silver.  Those  of  the  lat- 
ter, which  are  blackened  by  light,  are  of  themselves  in- 
soluble in  water  ;  and  it  is  difficult  to  impregnate  paper 
with  them,  in  an  equable  manner.  The  blackening  seems 
to  be  caused  by  the  formation  of  oxide  of  silver.  In  the 
case  of  the  bichromate  of  potash,  again,  that  salt  is  ex- 
ceedingly soluble,  and  paper  can  be  easily  saturated  with 
it.  The  agency  of  light  not  only  changes  its  color,  but 
deprives  it  of  solubility,  thus  rendering  it  fixed  in  the  pa- 
per. This  action  appears  to  me  to  consist  in  the  disen- 
gagement of  free  chromic  acid,  which  is  of  a  deep  red 
color,  and  which  seems  to  combine  with  the  paper.  This 
is  rendered  more  probable,  from  the  circumstance,  that 
the  neutral  chromate  exhibits  no  similar  change. 

The  active  power  of  the  light,  in  this  instance,  resides 
principally  in  the  violet  rays,  as  is  the  case  with  the  black- 
ening of  the  salts  of  silver.  To  demonstrate  this,  three 
similar  flat  bottles  w^re  filled,  one  with  ammoniuret  of 
copper,  which  transmits  the  violet  rays,  one  with  bichro- 
mate of  potassa,  transmitting  the  yellow  rays,  the  third, 
with  tincture  of  iodine,  transmitting  the  red  rays.  The 
paper  was  readily  acted  on  through  the  first,  but  scarcely, 
if  at  all,  through  the  seconc  and  third  ;  although  much 
more  light  passed  through  the  bottle  filled  with  bichromate 
of  potassa,  than  through  the  one  filled  with  ammoniuret 
of  copper. 

The  best  mode  of  preparing  paper  with  bichromate  of 
potash  is,  to  use  a  saturated  solution  of  that  salt ;  soak 
the  paper  well  in  it,  and  then  dry  it  rapidly,  at  a  brisk 
fire,  excluding  it  from  daylight.  Paper,  thus  prepared, 
acquires  a  deep  orange  tint,  on  exposure  to  the  sun.  If 
the  solution  be  less  strong,  or  the  drying  less  rapid,  the 
color  will  not  be  so  deep. 

A  pleasing  variety  may  be  made,  by  using  sulphate  of 
indigo  along  with  the  bichromate  of  potash,  the  color  of 
the  object,  and  of  the  paper,  being  then  of  different  shades 


PHOTOGENIC  DRAWING.  367 

of  green.     In  this  way,  also,  the  object  may  bq  repre- 
sented of  a  darker  shade  than  the  ground. 

Paper,  prepared  with  bichromate  of  potash,  is  equall}/ 
sensitive  with  most  of  the  papers,  prepared  with  salts  of 
silver,  though  inferior  to  some  of  them.  It  is  not  suffi 
ciently  sensitive  for  the  camera  obscura,  but  answers  quite 
well  for  taking  drawings  from  dried  plants,  or  for  copying 
prints,  &c.  Its  great  recommendation  is,  its  cheapness, 
and  the  facility  with  which  it  can  be  prepared.  The  price 
of  the  bichromate  of  potash  is  2s.  6d.  per  lb.,  whereas, 
of  the  nitrate  of  silver,  only  half  an  ounce  can  be  obtained 
for  that  sum.  The  preparing  of  paper,  with  the  salts  of 
silver,  is  a  work  of  extreme  nicety,  whereas,  both  the 
preparing  of  the  paper  with  the  bichromate  of  potash,  and 
the  subsequent  fixing  of  the  images,  are  matters  of  great 
simplicity ;  and  I  am  therefore  hopeful,  that  this  method 
may  be  found  of  considerable  practical  utility,  in  aiding 
the  operations  of  the  lithographer. — Jameson's  Journal^ 
Apiil  to  July,  1839 


GLOSSARY. 


Many  words,  not  contained  in  this  Glossary,  will  be  found  de* 
fined  or  described,  in  the  body  of  the  Work,  in  their  proper  places. 
For  these,  see  Index. 

Acescent,  becoming  sour. 

Acetate,  a  salt,  containing  acetic  acid. 

Acetic  acid,  a  vegetable  acid  which  exists  in  vinegar. 

Acetous,  having  the  character  of  vinegar. 

Acetous  fermentation,  the  fermentation  which  produces  vinegar. 

Acicular,  shaped  like  needles. 

Acid,  a  substance,  or  fluid,  which  turns  vegetable  blues  to  a  red,  and 

forms  saline  compounds  with  alkalies,  &c.     Most  of  the  acids  con- 
tain oxygen. 
Albumen,  a.  fluid  found  in  living  bodies,  which  coagulates  by  heat. 

White  of  egg  is  an  example. 
Alkali,  a  substance  in  chemistry,  which  turns  vegetable  blues  to  a 

green,  and  combines  with  acids,  forming  salts. 
Alloy,  a  compound  of  different  metals. 
Alumine,  an  earth,  which  exists  in  clay,  alum,  &c. 
Aluminium,  a  metal,  which  is  the  basis  of  alumine. 
Amalgam,  a  compound  of  mercury  with  another  metal. 
Ammonia,  volatile  alkali. 

Amorphous,  not  having  a  determinate  or  certain  form. 
Argillaceous,  containing  clay,  or  resembling  it. 
Argillaceous  schist,  common  slate. 
Arseniuret,  a  compound  with  arsenic. 
Barilla,  the  ashes  of  certain  maritime  plants. 

Barometer,  an  instrument  for  measuring  the  weight  of  the  atmosphere. 
Base,  an  ingredient  in  a  chemical  compound.     Thus,  sulphuric  acid  is 

found  combined  with  various  bases,  such  as  soda,  magnesia,  &c. 
Bichloride,  a  double  chloride.     A  compound,  having  two  proportionals 

of  chlorine. 
Boracic  acid,  a  compound  of  oxygen  and  boron,  which  last  is  a  simple 

combustible  substance. 
Borates,  compounds  of  boracic  acid  with  a  base. 
Brake,  or  Break,  a  lever,  which  is  occasionally  pressed  down  upon  the 

wheel  of  a  carriage,  to  retard  its  velocity. 
Bromide,  a  compound  of  bromine  and  some  other  substance. 
Bromine,  an  elementary  substance,  related  to  iodine  and  chlorine,  and 

found  in  sea  water. 


370  '  GLOSSARY. 

Camera  lucida,    >  optical  instruments,  by  which  the  images  of  ob- 
Cainera  obscura,)  }ects,   as,  for    example,   buildings    or   trees,    are 

thrown  upon  a  paper,  or  other  plane  surface. 
Carbonaceous,  containing  carbon  or  coal. 
Carbon,  a  simple  inflammable  body,  forming  the  principal  part  of  wood 

and  coal,  and  the  whole  of  the  diamond. 
Carbonate,  a  compound  or  a  salt,  containing  carbonic  acid. 
Carbonic  acid,  a  compound  gas,  consisting  of  carbon  and  oxygen.     It 

has  lately  been  obtained  in  a  solid  form. 
Carbonic  oxide,  a  gas  composed  of  carbon  combined  with  the  smal- 
lest quantity  of  oxygen. 
Carbojiization,  conversion  into  coal. 
Carburetted  hydrogen,  a  gas,  composed  of  carbon  and  hydrogen  ;  as 

coal  gas. 
Carburet,  a  name   given  to  certain  compound  substances,  of  which 

carbon  forms  a  part. 
Caseous,  having  the  consistence  of  cheese. 
Centre  of  gravity,  that  point  in  a  body,  about  which  all  the  parts  are 

equally  balanced. 
Centrifugal,  tending  to  fly  off"  from  the  centre. 
Chloride,  a  compound  of  chlorine  and  some  other  substance. 
Chlorine,  a  simple  substance,  formerly  called  oxymuriatic  acid.     In 

its  pure  state,  it  is  a  gas,  and,  like  oxygen,  supports  the  combustion 

of  some  inflammable  substances. 
Chromate,  a  combination  of  chromic  acid. 
Chromium,  a  brittle  metal,  of  a  yellowish  white  color. 
Chromic  acid,  an  acid  of  which  chromium  is  the  basis. 
Chromate,  a  compound  of  chromic  acid  with  some  other  substance,  or 

base. 
Clay  schist,  common  slate. 
Cohesive  attraction,  the  force  by  which  the  particles  of  a  body  cohere 

together. 
Coluber,  a  snake,  having  plates  on  the  belly  and  scales  on  the  tail. 
Comparative  anatomy,  the  science  which  treats  of  the  structure  of 

other  animals,  compared  with  that  of  man. 
Concentric,  having  the  same  centre. 
Conic  sections,  the  curves  produced  by  cutting  across  a  cone,  in  diff*er 

ent  directions. 
Cupreous,  containing  copper. 

Cycloid,  the  curve  described  by  a  point  in  the  circumference  of  a  cir- 
cle, \^hile  the  circle  rolls  along  a  straight  line. 
Cylinder,  a  figure  with  circular  ends  and  straight,  parallel  sides.     A 

round  ruler  and  a  wafer  box  are  rough  examples  of  the  cylindrical 


Debris,  fragments,  or  remains,  of  disintegrated  rocks. 

Deliquescent,  dissolving  by  fluid  absorbed  from  the  atmosphere. 

Disintegrated,  broken  up  or  crumbling,  for  the  most  part,  by  the  ac- 
tion of  air  and  moisture. 

Eccentric,  or  excentric.  This  term  is  applied  to  a  wheel,  the  axis  of 
which  is  not  in  its  centre. 

Effervescence,  a  motion  resembling  boilini;. 


GLOSSARY.  *  371 

Efflorescence,  the  conversion  of  crystals  into  powder  by  the  loss  of 
their  water  of  crystallization. 

Electro-magnetism,  a  science  which  shows  the  connexion  of  elec- 
tricity and  magnetism. 

Epicycloid,  the  curve  described  by  a  point  in  the  circumference  of 
one  circle,  while  rolling  upon  the  circumference  of  another. 

Flange,  or  Flanch,  a  rim,  or  part  projecting  from  the  whole  circum- 
ference. Flanges  are  used  in  the  wheels  of  rail-road  cars,  to  pre- 
vent them  from  slipping  off  the  track  ;  also,  at  the  ends  of  iron  pipes, 
to  enable  them  to  be  screwed  together. 

Flocculent,  resembling  locks  of  down,  or  cotton. 

Fluate  of  lime,  or  Fluor  spar,  lime  combined  with  fluoric  acid.  At 
Derbyshire,  in  England,  it  is  found  in  crystalline  masses,  beautifully 
variegated  with  purple. 

Flush,  even,  or  in  the  same  surface. 

Friction,  the  rubbing  of  surfaces  together. 

Friction  rollers,  little  wheels,  or  cylinders,  used  to  diminish  friction. 

Fulcrum,  the  point  of  support  on  which  a  lever  rests. 

Gallate,  a  salt,  formed  of  gallic  acid  and  a  base. 

Gallic  acid,  an  acid  obtained  from  nutgalls. 

Gear,  the  teeth  of  wheels,  by  which  one  moves  another. 

Gelatin,  an  animal  substance  which  is  dissolved  by  hot  water,  ana 
which  forms  common  glue. 

Geognostic,  appertaining  to  a  knowledge  of  the  earth's  structure. 

Geological  strata,  the  natural  layers  which  are  met  with  in  penetra 
ting  the  earth. 

Gneiss,  stratified  granite. 

Gobelins,  the  name  of  a  celebrated  manufactory  of  tapestry  in  Paris  , 
so  called,  after  two  brothers  of  that  name,  who  founded  the  manufac- 
tory in  the  reign  of  Francis  I. 

Gravity,  the  general  property  by  which  bodies  are  attracted  towards 
each  other,  as  seen  in  a  stone  falling  towards  the  earth. 

Graywacke,  a  kind  of  rock,  of  a  gray  or  brown  color,  comp  >sed  of 
grains  and  fragments  of  different  materials. 

HcBmatite,  an  ore  of  iron. 

Hydrate,  a  solid  compound  with  water. 

Hydrate  of  lime,  a  solid  compoimd  of  lime  with  water. 

Hydraulics,  the  science  which  treats  of  the  motion  of  fluids. 

Hydraulic  cement^  mortar, which  hardens  underwater. 

Hydrochlorate,  a  salt  containing  hydrochloric,  or  muriatic,  acid. 

Hydrochloric  acid,  see  Muriatic  acid. 

Hydrodynamics,  the  science  which  treats  of  the  power  or  force  of 
water. 

Hydrogen,  a  very  light,  inflammable  gas,  of  which  water  is,  in  part, 
composed.     It  is  used  to  inflate  balloons. 

Hydrostatic  pressure,  the  property  of  fluids  by  which  they  press 
equally  in  all  directions. 

Hydrostatics,  the  science  which  treats  of  the  pressure  of  fluids. 

Hydrosulphuret,  a  compound  of  hydrogen  and  sulphur  with  another 
body. 

Hyperbola,  one  <f  the  conic  sections. 


372  *  GLOSSARY. 

Hyposulphite,  a  combination  of  hyposulphurous  acid  with  a  oase  ,  as, 
for  example,  with  soda. 

Inclination,  slant,  slope,  or  obliquity. 

Inertia,  the  tendency  which  a  body  has  to  continue  at  rest,  or  to 
move  in  a  straight  line,  if  it  moves  at  all. 

Infiltration^  the  penetration  of  a  fluid  into  the  pores  of  a  solid,  as  m 
soaking. 

Infusion,  a  solution  of  a  vegetable  substance,  made  without  boiling. 

Initial,  that  which  exists  at  the  first  moment.     Primary,  incipient. 

Inspissated,  thickened,  as  when  the  juice  of  a  plant  is  partly  dried. 

Iodine,  a  simple  substance,  of  a  grayish  black  color,  and  metallic  lus- 
tre, having  a  violet-colored  vapor.  It  is  obtained  from  marine 
plants. 

Iridium,  a  metal,  found  in  minute  quantities  in  the  ores  of  platinum. 

Kelp,  the  ashes  of  seaweed. 

Larv(B,  the  name  given  to  certain  insects  in  their  primary  state,  be- 
fore they  acquire  wings  ;  as  the  caterpillar. 

Litharge,  an  oxide  of  lead  partly  vitrified,  or  converted  into  glass. 

Magnesia,  a  kind  of  earth,  light  and  white,  with  alkaline  properties. 

Malachite,  an  ore  of  copper. 

Malic  acid,  a  vegetable  acid  which  exists  in  cider. 

Minimum,  the  smallest  quantity. 

Momentum,  the  force  possessed  by  a  body  in  motion,  made  up  of  its 
weight  and  velocity. 

Muffle,  a  vessel  resembling  a  little  oven,  placed  in  furnaces  to  contain 
crucibles  and  other  objects,  which  require  to  be  protected  from 
smoke  and  ashes. 

Muriate,  a  salt,  containing  muriatic  or  hydrochloric  acid. 

Muriatic  acid,  an  acid,  composed  of  chlorine  and  hydrogen  ;  called, 
also,  hydrochloric  acid,  and  spirit  of  salt. 

JVitrate,  a  salt,  containing  nitric  acid. 

JVitric  acid,  an  acid  composed  of  oxygen  and  nitrogen. 

JVitrogen,  or  azote,  a  simple  substance,  which  exists,  in  the  form  of 
gas,  in  the  atmosphere.     It  does  not  support  respiration  nor  flame. 

Ochre,  an  earth  colored  yellow  or  red  by  oxide  of  iro«. 

Ochreous,  containing  ochre. 

Orrery,  a  machine,  constructed  to  show  the  motions  of  the  heavenly 
bodies. 

Osmium,  a  metal,  found  in  minute  quantities  in  the  ores  of  platinum. 

Oxalic  acid,  a  vegetable  acid  which  exists  in  sorrel. 

Oxidable,  capable  of  being  oxidized. 

Oxidation,  combination  with  oxygen  ;  as  in  the  rusting  and  tarnishing 
of  metals. 

Oxide,  a  compound  (which  is  not  acid)  of  a  substance  with  oxygen  : — 
Example,  ox'de  of  iron. 

Oxygen,  a  simple  and  very  important  substance,  which  exists  in  the 
atmosphere,  and  supports  the  breathing  of  animals  and  the  burning 
of  combustibles. 

Oxymuriatic  acid,  see  Chlorine. 

Parallelogram,  an  oblong  square. 

Parallelopiped,  a  solid  body,  of  which  the  four  sides  are  parallelo- 
grams, and  the  two  ends  square. 


GLOSSARY.  ..  373 

Piles,  large  wooden  posts  or  timbers,  driven  into  the  mud,  to  st4ppo»^ 
bridges  and  other  structures. 

Piling  engines,  engines  for  driving  piles. 

Plasticity,  the  property  or  capacity  of  being  moulded. 

Pontoon^  a  kind  of  flat-bottomed  boat,  used  to  support  bridges,  float- 
ing machinery,  &c. 

Potass,  an  alkali,  composed  of  potassium  and  oxygen. 

Potassium,  a  light  and  very  inflammable  metal,  discovered  in  potass, 
by  Sir  H.  Davy. 

Power  of  a  number,  the  product  obtained  by  multiplying  a  number  by 
itself.  The  product  obtained  by  the  first  multiplication  is  called  the 
square.  If  this  be  again  multiplied  by  the  same  number,  it  gives 
the  cube  ;  and  so  on,  for  the  higher  powers. 

Precipitation.  When  a  substance,  dissolved  in  a  liquid,  is  afterwards 
separated,  in  a  solid  state,  by  the  addition  of  another  substance,  it 
is  said  to  be  precipitated. 

Purple  of  Cassius,  a  purple  powder,  precipitated  from  a  solution  of 
gold. 

Pyrites,  a  compound  of  a  metal  with  sulphur,  having  a  metallic  lus- 
tre, and  often  crystallized. 

Pyritous,  having  the  charactes  of  pyrites. 

Pyrometer,  an  instrument  for  measuring  high  degrees  of  heat,  as  in 
furnaces,  &c. 

Radicles,  small  roots. 

Radius,  a  line  drawn  from  the  centre  of  a  circle  to  its  circumference. 

Reticulated,  resembling  the  appearance  of  a  net. 

Rhodium,  a  metal  found  in  minute  quantities  in  the  ores  of  platinum. 

Salt,  a  compound,  produced  by  the  union  of  an  acid  with  a  base. 

Saturated  solution,  a  liquid,  holding  so  much  of  a  substance  dissolv 
ed,  that  it  can  dissolve  no  more. 

Scalpel,  a  dissecting  knife. 

Schist,  or  Schistus,  slate. 

Sector  of  a  circle,  a  part  contained  between  two  radii  and  an  arc. 
The  sector  of  a  cylinder  is  a  longitudinal  part  which  bears  the  same 
relation  to  the  whole,  as  a  sector  does  to  a  circle. 

Silica,  or  silex,  an  earth  which  exists  in  flint,  sand,  &c. 

Silicium,  a  metal,  or  simple  substance,  which  is  the  basis  of  silica 

Sinuosities,  windings. 

Soda,  an  alkali,  obtained  from  the  ashes  of  marine  plants.* 

Spar,  a  general  name  given  to  crystallized  minerals. 

Stanniferous,  containing  tin. 

Stratification,  disposal  in  layers. 

Stratum,  plural  strata,  a  layer  of  earth,  rock,  or  (ther  mineral  sud» 
stance. 

Striated,  marked  with  fine  parallel  lines. 

Sulphate,  a  salt,  containing  sulphuric  acid. 

Sulphur,  or  brimstone,  a  simple,  inflammable  substance,  well  knowa 

Sulphuret,  a  compound  of  sulphur  with  another  body. 

Sulphitretted  hydrogen,  a  gas,  composed  of  sulphur  and  hydrogen. 

Sulphuret  of  carbon,  a  compound  of  sulphur  and  carbon. 

Sulphuric  acid,  an  acid  composed  of  oxygen  and  sulphur. 

II.  32  XII. 


374  GLOSSARY. 

Summit  level,  the  highest  part  of  a  canal,  or  rail-roacr. 

Tangent,  an  external  straight  line,  which  touches,  but  does  not  cross, 
a  circle. 

Tartaric  acid,  a  vegetable  acid  which  exists  in  wine. 

Thermae,  baths  of  the  Romans,  which  were  large  and  magnificent 
buildings. 

Thermal  waters,  warm  or  hot  springs. 

Thermometer,  an  instrument,  for  measuring  heat. 

Traction,  the  act  of  drawing  a  load.     Draught. 

Treenails,  (pronounced  trunnels,)  the  wooden  pins  which  confine  the 
planking  to  the  sides  of  vessels.  Also,  similar  pins,  employed  for 
other  purposes. 

Vacuum,  empty  space.  A  perfect  vacuum  is  rarely,  if  ever,  pro- 
duced. The  vacuum  of  the  air  pump,  and  that  of  the  barometer, 
are  approximations  only,  in  which  some  gas  or  vapor  is  present. 

Vaporization,  conversion  into  vapor,  commonly  at  a  boiling  temper 
ature. 

Velocipede,  a  carriage  with  two  wheels,  one  before  the  other,  on 
which  a  person  rides,  pushing  himself  forward  with  his  feet. 

Viaduct,  a  piece  of  masonry  built  across  a  stream  or  valley,  to  support 
a  road,  or  a  rail-way. 

Vice  versa,  the  side  being  changed,  or  the  question  reversed. 

Vitreous,  glassy. 

Water-joint,  a  movable  joint,  made  so  tight  as  to  exclude  water 


INDEX  TO  VOLUME  IL 


A. 

Accumulated  veins,  284. 
Adjustment  of  sails  for  windmills, 

98. 
Adzes,  246. 

Aerial  ascents  in  balloons,  49. 
Aerostation,  48. 

Ahaz,  sun-dials  in  the  time  of,  187. 
Aids  to  locomotion,  12. 
Air,     escape    of,    and    of   water, 

through  a  hole,  88.     See  Atmos- 
phere. 
Air-boxes  for  water  pipes,  140. 
Air-pumps  of  steam-engines,  118. 
Albany,  facts  as  to,  309.     Basin 

of  the  Erie  canal  at,  310. 
Albany  and  Schenectady  rail-way, 

cost  of  the,  325. 
Alkalies,  in  glass,  248. 
Alleghany  Mountains,  passes  across 

the,  331. 
Alleghany    rail-way,     299,    334. 

Facts  respecting  the,  328.     See 

Rail-ways. 
Alloys,  of  metals,  211.     Of  gold, 

214.     Experiments  of  Hatchet 

and  Cavendish  with,  215,  note. 

With  silver,  219.     Brass,  223. 

Bronze,  225.     Gun-metal,  225. 

Bell-metal,  225,   226.     Specu- 
lum-metal, 225,  226. 
Alternate,  or  reciprocating,  motion, 

62. 
Amalgams,  211.     Gold  extracted 

by,  212. 
Amboy   and    Camden    rail-road, 

322,  334. 
American,  enterprise,  298.     Rail- 


ways, 298,  299,  318,  334.     Ca- 
nals, 299,  301,  314. 

Ancient  coins,  experiments  on,  by 
Dize,  226,  note. 

Animal  power,  82.  Of  men,  82. 
Of  horses,  84. 

Animals,  motion  of,  9,  10. 

Annealing,  metals,  216,  note. 
Glass,  251. 

Antimony,  used  for  coloring  glass, 
258.     Localities  of,  287. 

Appendages  to  steam-engines,  110. 

Apron,  87. 

Aqueducts,  canal,  33,  304.  Con 
veying  of  water  in,  135.  Ro 
man,  136. 

Arbor,  meaning  of,  195,  note. 

Arch  of  the  Schuylkill  bridge,  22. 

Archimedes'  screw,  144. 

Arcs,  line  of,  described  in  walk 
ing,  10. 

Arkwright,  Sir  Richard,  water 
spinning-frame  by,  168. 

Arrago,  experiments  by,  on  steam, 
102,  note. 

Arrangement  of  pipes,  156. 

Arrow-headed  character,  263. 

Artesian  wells,  275.  Operations 
in  forming,  276.  Cause  of  the 
overflowing  of,  276.  Tools 
used  in  digging,  277.  Finish- 
ing of,  278. 

Artificial,  fountains,  161.  Gems, 
258. 

Artillery,  metal  for,  225. 

Artois,  overflowing  wells  in,  275. 

Arts,  of  locomotion,  9.  Moving 
forces  used  in  the,  81.    Of  con- 


376 


INDEX. 


veying  water,  135.  Of  com- 
bining flexible  fibres,  164.  Of 
horology,  187.  Of  metallurgy, 
208.  Of  vitrification,  247.  Of 
induration  by  heat,  262. 

Ascents  in   balloons,  49. 

Assaying  metallic  ores,  210. 

Athens,  sun-dials  on  the  Tower  of 
the  Winds  at,  188.  Brick  walls 
of,  262. 

Atmosphere,  effect  of,  on  overshot 
wheels,  remedied,  88.  Pres- 
sure of,  upon  steam,  101,  102. 
See  Air. 

Atmospheric  elastic  force,  104. 

Atmospheric  engine  of  Newco- 
men,  115,  120. 

Atmospheric  machines,  159. 

Attaching  of  horses,  14,  18,  84. 

Augusta  and  Charleston  rail-road, 
322.     Cost  of  the,  325. 

Axes,  244,  246. 

Axis,  meaning  of,  195,  note. 

Axle,  meaning  of,  195,  note. 

Axletrees,  17. 

B. 

Babylon,  the  walls  of,  brick,  262. 

Back-water,  remedies  for,  92,  93. 

Bag  pumps,  153. 

Balance-wheels  of  watches,  191, 
192,  203. 

Ballast,of  aship,  41.  Of  balloons, 
48. 

Balloons,  48.     Ascents  in,  49. 

Baltimore  and  Ohio  rail-way,  325, 
335. 

Baltimore  and  Washington  rail- 
way, 320,  335. 

Band,  73. 

Band  wheels,  51 

Bar-iron,  235. 

Barker's  mill,  96. 

Barrels,  of  watches,  191,200,201. 
Of  clocks,  195,  197. 

Barton's  pistons,  122. 

Basin  of  the  Erie  canal,  at  Alba- 
ny, 310. 

Baskets,  plated,  222. 

Batchelder,  loom  by,  for  weaving 
twilled  fabrics,  176. 


Bath-metal,  224. 

Baths,  Parkes's  metallic^  244 
Roman,  of  brick,  262. 

Bailer,  cotton,  169. 

Batting  cotton,  169. 

Bayonets  of  couplings,  76. 

Bead  pumps,  157. 

Beak  iron,  245. 

Beam,  wind  upon  the,  39. 

Beating,  gold,  215. 

Beet  sugar,  manufacture  of,  339  , 
cleansing  of  the  beet  roots,  339  ; 
rasping  the  beets,  341  ;  extrac- 
tion of  the  juice,  342  ;  mode  of 
operating  with  the  press,  343  ; 
defecation  of  the  juice,  343  ; 
concentration  of  the  juice,  344. 
Clarifying,  344.  Filtration,  346. 

Belgium,  rail-way  in,  318. 

Bell-metal,  225,  226. 

Belt  and  segment,  71. 

Bernouilli,  oblique  planes  recom- 
mended by,  42. 

Berthier,  alloy  produced  by, 
242. 

Besant's  wheel,  93. 

Bevel-gear,  56. 

Biddery-ware,  229. 

Binding,  See  Bookbinding. 

Birds,  the  flying  of,  10.  Swim- 
ming of,  11. 

Biscuit,  in  pottery,  270. 

Bismuth,  localities  of,  287. 

Blades  of  cutlery,  245. 

Blair's  gap,  pass  through,  331. 

Blanks,  in  coining,  219. 

Blast,  hot,  in  smelting  furnaces, 
233. 

Blasting,  with  gunpowder,  134, 
292.  Tools  of  miners  for,  290. 
In  mines,  292.  Sawdust  used 
in,  293. 

Blast-furnaces,  232. 

Bleaching  rags  for  paper,  184. 

Blistered-steel,  240. 

Block-tin,  229. 

Blooms,  236. 

Blotting  paper,  184. 

Blowing  glass,  250. 

Blow-valves,  118. 

Boats,  transferring,  on  canals,  36 


INDEX. 


377 


Canal,  36.  Powers  in,  which 
act  against  the  inertia  of  water, 
42.     Passenger  canal,  306. 

Bobbins,  171,  172. 

Bohemia,  rail-way  in,  318. 

Boilers  of  steam-engines,  108. 
Strongest  form  for,  108.  Flue, 
108.  In  large  low-pressure  en- 
gines, 109.  Bursting  of,  112. 
Other  forms  for,  113.  Mate- 
rials for,  117. 

Bologna-phials,  251. 

Bonnet,  glass  fibres  obtained  by, 
261. 

Bookbinding,  the  process  of,  185. 
Cloth,  186. 

Borers,  use  of,  in  digging  Artesian 
wells,  277.  Used  by  miners, 
290,  297. 

Bosses,  245. 

Bossut,  on  the  inclination  of  float- 
boards,  92. 

Boston  and  Lowell  Railroad,  319, 
334. 

Boston  and  Providence  rail-road, 
321,  334. 

Boston  and  Worcester  rail-road, 
327,  334. 

Bottle-glass,  252. 

Boulton,  coining  machinery  by, 
220. 

Bow  of  a  ship,  38. 

Bowing  materials  for  hats,  183. 

Boxes,  pump,  148. 

Brakes,  retarding  wheels  by,  31. 
Of  a  pump,  148. 

Bramah,  re-inventor  of  the  hy- 
drostatic press,  152.  Lead 
pipes  by,  228. 

Bramins,  sun-dials  among,  187. 

Branca,  engine  of,  103,  note. 

Brass,  composition  of,  223.  Man- 
ufacture of,  224.  Buttons,  224. 
Pins,  225. 

Brathwaite  and  Ericsson's  steam- 
engines,  113. 

Breakers,  in  caniing  machines, 
170. 

Breast-wheels,  85,  94. 

Brewster,  Dr.,  on  the  adaptation 
of  wheels  to  falls,  88,  7Wte. 

32* 


Brick-kilns,  264. 

Bricks,    ancient,   262.      Modern, 

263.     Pressed,    263.     Burning 

of,  264. 
Bridges,  21.    Wooden,  21.     The 

Schuylkill,    22.        Stone,    22. 

Cast-iron,  23.     Suspension,  23. 

At  Menai,  23,  125.     Floating, 

23. 
Bridgewater,  Duk3  of,   tunnel   in 

the  canal  of  the,  34. 
British  Queen  steam-ship,  45. 
Broadcloths,  nap  of,  182. 
Broad  glass,  251. 
Broad  wheels,  15. 
Bronze,  225. 
Brooklyn  and   Jamaica  rail-road, 

322,334.    Cost  of  iron  for,  324, 

Sleepers  on  the,  324. 
Brown's  gas  engines,  128. 
Brush  wheels,  58. 
Brussels,  watch-spring  preserved 

at,  190. 
Brussels  carpets,  178. 
Buchanan,  on  the  application  of 

human  power,  83. 
Buckets,  of  overshot  wheels,  86. 

Of  chain  wheels,  89.     In  breast 

wheels,  95. 
Buffalo  and  Niagara  rail-road,  321, 
-  334. 
Burning,  of  bricks,  263,  264.    Of 

pottery,  269. 
Burns,  buckets  of,  in  the  overshot 

wheel,  87.     Method   of  getting 

rid  of  back-water  by,  92. 
Bursting  of  boilers,  112. 
Bushnell's  machine  for  submarine 

navigation,  47. 
Buttery,  on  carbon  in  steel,  241, 

note. 
Buttons,    manufacture    of   brass, 

224  ;  of  the  eye  or  shank,  224. 

White-metal,  224.     Brass-eyes 

of  pearl,  224. 


Cables,  166. 
Caledonian  canal,  36. 
Camden    and     Amh.y   raiUway, 
322,  334. 


37S 


INDEX. 


Camera  obscura,  use  of  the,  in 
photogenic  drawing,  356. 

Cams,  63.     Curves  for,  64,  note. 

Canal  boats,  36.  On  the  Erie 
canal,  305.     Passenger,  306. 

Canals,  rail-roads  and,  24.  Feed- 
ers of,  32.  Embankments  of,  32. 
Aqueducts  in,  33,  304.  Tun- 
nels for,  33.  Gates  and  weirs 
for,  34,  308.  Locks  in,  34, 
303,  308.  Economizing  water 
in,  35.  Boats  for,  36,  305, 
306.  Size  of,  36.  The  Great 
Dutch,  36.  The  Caledonian, 
36.  Languedoc,  37,  301.  New 
York,  or  Erie,  37,  300,  308, 
315.  In  the  United  States,  298, 
314  ;  their  extent,  299  ;  routes 
of  the  principal,  300.  Historical 
facts  respecting,  301.  Length  of 
the  American,  301,  314  ;  their 
cross-sectional  area,  302.  Ve- 
locity of  wave  in,  302.  Dis- 
similarity in  American  and  Brit- 
ish, 303.  Suspension  of  the 
American,  in  winter,  305;  mode 
of  travelling  on  them,  306. 
Slackwater-navigation  in  the 
lines  of,  307.  Details  respec- 
ting the  Erie,  308,  315.  The 
Morris,  311,  315.  Table  r«- 
specting  the  United  States',  314. 
Eastern  division  of  the  Pennsyl- 
vania, 315,  330. 

Cannon,  casting  of,  239. 

Cannon-balls,  234. 

Cannon-pinion  of  watches,  206. 

Carats  of  gold,  214. 

Card-ends,  171. 

Carding,  170. 

Carpets,  Kidderminster,  177,  178. 
Venetian,  178.  Brussels,  178. 
Turkey,  179. 

Carriages,  12.  Retarding,  31, 
note.     Steam,  129. 

Carronades,  manufacture  of,  239. 

Cartridges,  use  of,  in  mining,  292. 

Cartwright's  steam-engine,  67, 
122. 

Case-hardening,  242. 

Casting,    the    process     of,    233. 


Moulds   for,   233.     Chill,  234. 
Of  glass,  253.    Of  pottery,  269 

Cast-iron,  bridges  of,  23.  Con- 
dition of,  233.  Converted  into 
good  steel,  246.  Rails,  intro- 
duced, in  Great  Britain,  318. 

Cast-steel,  241. 

Cavendish  experiments  with  al- 
loys, 215,  note. 

Cayuga  canal,  308,  315. 

Cellular  pumps,  157. 

Cementation,  of  gold,  214.  Of 
steel,  240. 

Cenis,  Mount,  and  Simplon,  298. 

Centre-wheel  of  a  watch,  203. 

Centres,  line  of,  54. 

Centrifugal  pumps,  146 

Ceramic,  crystallo,  260. 

Chain,  wheels,  88.     Pumps,  157. 

Chains  of  watches,  190,  191,  200, 
201. 

Chairs  on  rail-ways,  25. 

Champlain  canal,  308,  315. 

Change,  of  velocity,  in  machinery, 
60.  Of  direction,  in  motion, 
74. 

Chariots,  12.      See  Carriages. 

Charleston  and  Augusta  rail-way, 
322.     Cost  of  the,  325. 

Chat  Moss,  rail-way  across,  323. 

Cheeks   of  rail-road  chairs,  322 

Chemung  canal,  308,  315. 

Chill-casting,  234. 

Chinese,  substitute  for  canal  locks 
by,  35.  Working  of  pumps  by, 
157.  Make  ropes  of  woody 
fibres,  166.  Sun-dials  known 
to  the,  187.  Pakfong,  or  white 
copper,  226.  Drawings  on  por 
celain  by  the,  270.  Porcelain, 
271.  Magic  porcelain  of  the, 
273. 

Choragic  monument  of  Lysicrates, 
265. 

Chrome,  used  for  coloring  glass, 
258. 

Church,  Edward,  compilation 
from  a  work  of,  on  beet  sugar, 
339. 

Circles,  the  moving  of  horses  in, 
while  drawing,  85. 


INDEX 


379 


Circular  motion,  51.  Distant,  59. 
In  Barker's  mill,  96. 

Circumferences,  primitive,  54. 

Clack  valves,  122. 

Clamps  of  bricks,  264. 

Clarification  of  beet  sirup,  344. 

Clay,  valuable  properties  of,  262. 
Products  from  indurated,  262. 
Pipe,  267 

Claying-bars,  291. 

Cleansing  beets   for    sugar,    339. 

Clepsydra,  construction  of  the, 
188.  Invented  in  Egypt,  188, 
note.  Brought  to  Rome  from 
Athens,  188,  note. 

Clocks,  189.  Water,  189.  Gene- 
ral principles  of,  190.  Maintain- 
ing power  of,  190.  Weights  of, 
190,  195.  Regulating  move- 
ment of,  191.  Pendulums,  191, 
195.  Scapements  of,  193.  De- 
scription of,  194.  Going  part 
of,  194.     Striking  part  of,  194, 

197.  Wheel-work  of,  194. 
Dial-work  of,  194.  Barrels  of, 
195,  197.  Pallets  in,  196,  198. 
Hands  of,  196.      Hawksbill  in, 

198.  Warning-pieces  in,  198. 
Close-hauled,  39. 
Cloth-binding  of  books,  186. 
Cloths,  woollen,  manufacture   of, 

181.  Felting,  182.    See  Cotton. 

Clutches  to  couplings,  76. 

Coals,  mechanical  virtue  of,  125. 

Coal-strata,  279. 

Cobalt,  used  for  coloring  glass, 
258.  Printing  ware  with  the 
oxide  of,  270.  Furnished  to 
Chinese  potters,  270,  note.  Pla- 
ces for  finding,  287. 

Coff'er-dams,  22. 

CcfFer-valves  of  steam-engines, 
117, 

Coining,  of  silver  and  other  me- 
tals, 219.  At  the  mint  in  Eng- 
land, 220.     Of  medals,  220. 

Coin=-posts,  for  canal-gates,  35. 

Coins,  experiments  of  Dize  on  an- 
cient, 226,  note.  Copying,  by 
voltaic  electrical  engraving,  349. 

Colcothar,  polishing   silver   with, 


219.      Polishing   cutlery   with, 
246. 

Colors  for  staining  glass,  256, 
258. 

Columbia  and  Philadelphia  rail- 
road, 321,  329,  334. 

Combining  flexible  fibres,  arts  of, 
164. 

Combs  in  carding  'tnachines,  170. 

Common  pinion  in  watches,  205. 

Common  pumps,  147. 

Compass,  magnetic,  used  by  mi- 
ners, 289  ;  dial  of,  289. 

Concentration  of  beet  juice,  344. 

Concretions,  in  geology,  280. 

Condensation,  application  of  steam 
by,  104,  120. 

Condensers,  invented  by  Watt, 
116,  120.  Remarks  on,  118, 
120.     Treadwell's,  121. 

Condensing  engines,  boilers  in, 
108,  109.  Construction  of, 
115. 

Conducting  water,  135.  By  aque- 
ducts, 135.  By  water  pipes, 
136.     By  syphons,  141. 

Conemaugh  river,  viaduct  across 
the,  332. 

Cones,  60. 

Consolidated  mines,  depth  of  the, 

-  298. 

Continued  rectilinear  motion,  73. 

Contrate  wheels ,  56.  Of  watches, 
203. 

Convoys,  retarding  by,  31. 

Copper,  gold  alloy,  215,  and  215, 
note.  Gilding  on,  216.  Plating 
on,  221.  Extraction  of,  222. 
Mines  of,  222.  Working,  223 
Tinning,  223.  Articles  made 
of,  223.  An  alloy  in  brass, 
223  ;  in  bronze,  225.  White, 
226.  Used  for  coloring  glass, 
258.     Places  for  finding,  286. 

Copper  pipes,  137. 

Cordage,  155.      See  Ropes. 

Cornwall,  steam-engine  at  St. 
Austle  in,  125.  Depth  of  minea 
in,  298. 

Cost  of  American  rail-ways,  325, 
326;  of  English,  325. 


380 


INDEX. 


Cotton,  manufacture  of,  167;  ele- 
mentary inventions  for  the,  168. 
Batting,  169.  Ginning,  169. 
Carding,  170.  Drawing,  170. 
Roving,  171.  Spinning,  172. 
Mule-spinning,  173.     Warping, 

174.  Dressing,  175.    Weaving, 

175.  Twilling,  176.  Double 
weaving,  177.  Cross-weaving, 
177. 

Cotton   rags,  paper  made  of,  183. 

Counterpanes,  180. 

Couplings,  75.  Clutches,  or  glands 
to,  76.     Bayonets  to,  76. 

Cranks,  59,  65. 

Crockery-ware,  265. 

Crompton,  Samuel,  invented  the 
mule,  169. 

Crooked  Lake  canal,  308,  315. 

Crossing  points  in  rail-ways, 
28. 

Cross-weaving,  177. 

Crown-glass,  249. 

Crown-wheels,  56.  Of  watches, 
204. 

Crucibles,  materials  for,  265. 

Crude-iron,  233. 

Cruikshanks,  on  water  from  com- 
bustion of  gunpowder,  131. 

Crutch  scapements,  72. 

Crystallo  ceramie,  260. 

Culverts  under  canals,  33. 

Cupellation  of  gold,  21.3. 

Cupels,  described,  213. 

Curb,  in  watches,  206. 

Cursor,  Papirius,  sets  up  a  sun- 
dial at  Rome,  188. 

Curves  upon  rail-ways,  28. 

Curves,  for  cams  and  wipers,  64, 
note.  In  pipes,  to  be  avoided, 
139,  140. 

Cut-glass  he  operation  of  making, 
255. 

Cutlery,  245.  Grinding,  246.  Pol- 
ishing, 246.     Setting,  246. 

Cut-nails,  239. 

Cutting  glass,  256. 

Cylinder-glass,  252. 

Cylindrical  wheels,  17. 

Cyrrhestes,  Andronicus,  Tower  of 
the  Winds  erected  bv,  188. 


D. 

Daguerre,  description  of  photo- 
genic drawing  by,  350.  See 
Photogenic  Drawing. 

Damascus  swords,  244,  note. 

Dams  for  slackwater-navigation, 
306.  Across  the  Schuylkill 
307  ;  the  Hudson,  309. 

Danforth's  speeder,  172. 

Danville  and  Pottsville  rail-road, 
325,  335. 

Dartrigues,  on  devitrification,  259. 

Davy,  Sir  Humphrey,  on  procuring 
power  from  fluids,  128. 

Dead  pulleys,  76. 

Dead  water,  37. 

Dectot,  Mannoury,  144. 

Deep  cuts,  25. 

Defecation  of  beet  juice,  for  sugar, 
343. 

De  La  Hire's  pump,  151. 

Dent,  on  a  dissected  watch,  208. 

Deparcieux,  M.,  on  the  line  of 
traction,  15.  Experiments  by, 
on  the  inclination  of  float-boards, 
92. 

Depots  of  American  rail-roads, 
328. 

Depth  of  mines,  297. 

Derangements,  in  mineral  veins, 
285. 

Desaguliers,  on  man's  and  horse's 
power,  84. 

Detonation  of  gunpowder,  130. 

Devitrification,  259. 

Dials,  sun,  187.  Of  compasses 
used  by  miners,  289. 

Dial-work  of  a  clock,  194. 

Diamonds,  in  watches,  207. 

Dilated,  or  flat,  veins,  283,  284. 

Direction, change  of,  in  machinery, 
74.    Of  a  mineral  plane,  280. 

Disengaging  machinery,  75. 

Disengaging  process,  in  photogenic 
drawing,  358. 

Dishing  wheels,   16,  17. 

Disseminated  metalliferous  sub- 
stances, 282. 

Distances,  in  the  route  from  New 
York  to  New  Orleans,  300. 

Distant  rotary  motion,  59. 


INDEX. 


381 


Diving-bells,  45.    Account  of,  45, 

46.     Sensations  in,  46. 
Dize,  experiments  by,  226,  note. 
Doffing-cylinders,  170. 
Doffing-plates,  170. 
Double-acting  engines,  description 

of,  116. 
Double-acting  pumps,  153. 
Double-speeders,   171.     Mechan- 
ism of,  171. 
Double-weaving,  177. 
Draught,  line  of,  14,  18,  84.     Of 

a  cotton  machine,  171. 
Drawing,  by  animals,  15,  18,  84. 

Of  cotton,    170.      Wire,    238. 

See  Photogenic  drawing. 
Drawing-frames,  170,  171. 
Draw-looms,  177. 
Dressing,  in  weaving,  175. 
Drops,  Rupert's,  251. 
Drymg  of  bricks,  262,  263. 
Dry-rot,    Kyan's    preparation    a- 

gainst,  324. 
Dublin    and  Kingstown  rail-way, 

319.     Cost  of  the,  325,  326. 
Ductility  of  glass,  260. 
Dulong,  M.,  on  steam,  102,  note. 
Dust,  on  tram-roads,  29. 
Dutch   canal,  the  great,   36,  302. 


Earth,  means  of  penetrating  into 
the,  290  ;  manual  tools,  290  ; 
gunpowder,  291  ;  fire,  294. 
See  Mines. 

Earthen,  pipes,  137,  note,  138. 
Ware, 265  ;  manufacture  of,266. 

Eccentric,  wheels,  63.  Pumps, 
155. 

Ecton  mine,  depth  of,  298. 

Edge  rail-ways,  25. 

Edges,  silver,  221. 

Eduction-pipes,  118. 

Egyptians,  the  manufacture  of 
linen  by  the.  181.  Sun-dials 
known  to  the,  187.  Clepsydra 
invented  by  the,  188,  note. 
Glass  among  the,  261.  Bricks 
of  the,  262.      Sec-Pyramids. 

Electrical  engraving,  voltaic,  348. 

Elementary  inventions  for  the  cot- 
ton manufacture,  168. 


Elements  of  machinery,  50. 

Eliquation  of  silver,  218. 

Elongation,  galleries  of,  295,  297 

Embankments  of  canals,  32. 

Enamelling  glass,  257.  Enamels 
for,  257.  Colorbg  materials 
for,  258. 

Enchasing,  215. 

Endless  screw,  57. 

Engaging  and  disengaging  ma- 
chinery, 75. 

Engines,  gas,  128.  Magnetic, 
134.  Fire,  162.  See  Steam- 
engines. 

England,  Artesian  wells  in,  275 
Wooden  tram-roads  introduced 
into,  318.  Cast-iron  rails  in- 
troduced in,  318.  Cost  of  rail- 
ways in,  325. 

Engraving,  voltaic  electrical,  348 

Enterprise,  American,  299. 

Epicycloidal  wheels,  69. 

Equalizing  motion,  76. 

Ericsson's  and  Brathwaite's  steam- 
engines,  113. 

Erie  canal,  37,300.  Length  of 
the,  300,  302,  315.  Number  of 
boats  navigating  the,  305.  Facts 
respecting  it,  308,  310,  315. 
Basin  of  the,  310. 

Etruscan  vases,  273. 

European  porcelain,  271. 

Evans,  high-pressure  expansion  ei 
gines  of,  106. 

Excavation,  instruments  for,  289. 
Means  of,  290  ;  manual  tools, 
290  ;    gunpowder,    291  ;    fire, 

294.  Formsof  the,  to  be  made, 

295.  See  Mines. 
Expansion,   application  of  steam- 
power  by,  106,  119.    Of  glass, 
261. 

Expansion  engines,  119. 

Expansiveness  of  water  in  steam, 
100. 

Explosions  of  steam-boats,  112. 

Extraction,  of  metals,  209.  Of 
gold,  212.  Of  silver,  217.  Of 
copper,  222.  Of  lead,  226. 
Of  tin,  229.  Of  iron,  232 
Of  beet  juice  for  sugar,  342. 

Eyes  of  brass  buttons,  224. 


382 


INDEX. 


F. 

Falls,     adaptation      of     overshot 

wheels  to,  88,  7iote. 
Faraday,  experiments  by,  on  steel, 

241. 
Faults,  in  mineral  veins,  285. 
Feed-pipes  for  steam-engines.  111. 
Feeders  of  canals,  32. 
Felting,  hats,   182.     Cloths,    183. 
Fen-wheels,  163. 
Ferrara,    Andrew,    tempering    of 

swords  by,  244,  note. 
Ferry-boats,     propulsion    of,    by 

horses,  85. 
Fibres,  arts  of  combining  flexible, 

164.     Woollen,  181.    Of  glass, 

260,  261. 
Filling  of  a  web,  175. 
Filtration  of  beet  sirup,  346. 
Finishers,    in    carding    machines, 

170. 
Fire,  employment   of,  in   raining, 

294. 
Fire-arms,  properties  of,  132. 
Fire-engines,  162. 
Fishes,    the    swimming    of,     10. 

Swimming  bladder  in,  11,  note. 
Flanges  on  rail-way  wheels,  25. 
Flash-wheels,  163. 
Flat,  or  dilated,  veins,  283,   284. 
Flax,  reward  offered  for  a  machine 

to  spin,  180. 
Flexible  fibres,  arts  of  combining, 

164.    . 
Flint,  use  of,  in  glass-making,  248, 

252.     Glass  ground  with,  254. 

In  Wedgewood's  ware,  268. 
Flint-glass,  252.      Moulding,  254. 
Float-boards,  propulsion  of  boats 

by,  42.     Affixed  to  a  chain,  89. 

In  under-shot  wheels,  90.    Best 

number  of,  91.    Position  of,  91, 

94.     Breadth   of,  92.     In    Be- 

sant's  wheels,  93.  In  Lambert's 

wheels,  94.     In  breast-wheels^ 

95. 
r'loating  bridges,  23. 
I  loors,  of  tiles,  264. 
Flue-boilers,in  steam-engines,  108. 
Fly,  78.     In  the  striking  part  of  a 

clock,  197. 


Fly-wheels,  78.  Of  steam-en* 
gines,  117. 

Flying,  locomotion  by,  10 

Foil,  tin,  229. 

Followers,  in  moulds  for  pressing 
glass,  255. 

Force  of  gunpowder,  131. 

Forces,  see  Moving  Forces. 

Forcing-pumps,  149. 

Forged-iron,  235. 

Forging,  235. 

Forks,  245.    Prongs  of,  245. 

Form  of  a  ship,  37. 

Formations,  geological,  279. 

Fountains,  Hero's,  140,  159.  Ar 
tificial,  161. 

Fourdrinier's  paper-machine,  184, 
185. 

Fowling-pieces,  manufacture  of, 
239. 

France,  canals  in,  37,  301,  303. 
IManufacture  of  porcelain  in, 271. 
Artesian  wells  in,  275.  Rail- 
ways in,  318. 

Frenchtown  and  Newcastle  rail 
way,  320. 

Friction,  locomotion  opposed  by,  9. 
Obviated,  in  walking,  10.  Angle 
for  obviating,  in  drawing,  15, 
18,  84.  In  machinery,  79 
Of  pipes,  138. 

Frit,  of  glass,  250. 

Fritting  glass,  250. 

Frost,  prevention  of,  on  rail-ways, 
322. 

Fuel,  of  engines,  125.  Used  on 
rail-ways,  328. 

Fulling  cloths,  181. 

Fulton,  Robert,  preferred  planes 
to  canal  locks,  35.  Introduc- 
tion of  steam-navigation  by,  42. 
Experiments  by,  on  submarine 
navigation,  47.  His  torpedo, 
48. 

Furnaces,  in  steam-engines,  116. 
Blast,  232.     Puddling,  235. 

Fusees  of  watches,  62,  191,  200— 
202. 

Fuses,  used  in  blasting,  290. 

Fyfe,  on  the  Chinese  pakfong, 
226. 


INDEX. 


383 


Gads,  used  by  miners,  290. 

Galena,  226. 

Galleries,  in  mines,  295.  Acceler- 
ating the  advance  of,  296. 

Gallic  coins,  experiments  on,  by 
Dize,  226,  note. 

Gangues,  of  metals, 209.  Of  lodes, 
282.  Value  of,  to  miners,  285, 
288.^ 

Garnerin,  M.,  parachute  of,  49. 
Aerial  voyage  of,  49,  note. 

Gas  engines,  128. 

Gates,  in  canals,  34. 

Gathered,   in  glass-blovping,   250. 

Gathering-pallet  in  a  clock,  198, 
199. 

Gauge-cocks,  in  steam-engines, 
111. 

Gauze- vpeaving,  177. 

Gay-Lussac,  ascension  of,  49,  note. 

Gear  or  gearing,  meaning  of,  53. 
Spur,  53.  Spiral,  55.  Bevel, 
56.  Wheels  thrown  into  and 
out  of,  76. 

Gems,  artificial,  258. 

Generation,  application  of  steam 
by,  105. 

Generators,  in  Perkins's  engines, 
113,  note. 

Geological  formations,  or  deposits, 
279. 

Geology,  value  of,  in  investigating 
mines,  287. 

Geometry  aids  the  miner,  289. 

German  silver,  226. 

Germany,  Artesian  wells  in,  275. 

Gerstner,  rail-way  by,  318. 

Gilding,  on  metals,  216.  On  por- 
celain, 272. 

Gilt  wire,  217. 

Ginning  cotton,  169. 

Glands  of  couplings,  76. 

Glass,  248.  Materials  composing, 
248.  Metals  of,  248,  note. 
Crown,  249.  Fritting,  250. 
Melting,  250.  Blowing,  250. 
Annealing,  251.  Broad,  251. 
Flint,  252.  Bottle,  252.  Cylin- 
der, 252.  Plate,  253.  Casting, 
253       Polishing     plate,     254. 


Ground  with  pure  flint.  254. 
Moulding,  254.  Pressing,  255. 
Cutting,  255.  Stained,  256. 
Enamelling,  257.  Artificial  gems 
made  of,  258.  Devitrification 
of,  259.  Reaumur's  porcelain 
from,  259.  Crystallo  ceramie, 
260.  Thread,  260.  Remarks 
on,  261.  Expansion  of,  261. 
Invention  of,  261. 

Glass  globes,  silvering  the  inside 
of,  231. 

Glass  thread,  260. 

Glass  windows,  261. 

Glazing  ware,  267,  270. 

Globes,  glass,  silvering  the  inside 
of,  231. 

Gneiss,  metalliferousness  of,  282, 
283. 

Gobelins,  manufactory  of  tapestry 
by  the,  179. 

Going  part  of  clocks,  194. 

Gold,  212.  Extraction  of,  212. 
Cupellation  of,  213.  Parting, 
213.  Quartation  of,  214.  Ce- 
mentation of,  214.  Alloy  in,  214. 
Working,  215.  Beating,  215. 
Leaf,  216.  Party,  216.  Gilding 
metals  with,  216.  Wire,  217. 
Thread,  217.  Improvements  by 
Stoddart,  in  gilding  with,  217, 
note.  A  coloring  material  for 
glass,  258.  Localities  of, 
286. 

Gold-beating,  215. 

Gold-leaf,  216. 

Gold-lustre  ware,  273. 

Goldsmiths'  work,  215. 

Gold-thread,  217. 

Gold  wire,  217. 

Governors,  in  steam-engines,  7b, 
110,  117.  In  water  wheels,  77. 
In  windmills,  99. 

Grading  rail-ways,  24. 

Graduated  semicircle,  used  by 
miners,  289. 

Granite,  combustible  fossils  not 
found  in,  288. 

Granite  blocks,  rail-roads  on,  319, 
323. 

Gravity,  an  obstacle  to  locomotion, 


384 


INDEX 


9,  11.     Water  and  wind,  appli- 
cations of  the  force  of,  85. 

Great  Dutch  canal,  in  Hx)Iland, 
36,  302. 

Great  Western  steam-ship,  Lieu- 
tenant Hosken,  commander  of 
the,  44,  note.     Size  of  the,  45. 

Great  wheel  of  a  watch,  203. 

Greek  coins,  experiments  on,  by 
Dize,  226,  note. 

Gregory,  Dr.,  on  obviating  friction, 
15. 

Grinding  of  cutlery,  246. 

Gripes,  in  nail-machines,  239. 

Grubbing  rail-ways,  331. 

Guanaxuato,  depth  of  a  mine  in, 
298. 

Guard-gut  of  a  watch,  202. 

Gudgeons,  meaning  of,  195,  note. 

Gun-making,  239. 

Gun-metal,  225. 

Gunpowder,  substitution  of  steam 
for,  129.  Manufacture  of,  130. 
Detonation  of,  130.  Force  of, 
131.  Firing,  133.  Blasting  with, 
134.  Value  and  use  of,  in 
mining,  291,  296.  Augmenta- 
tion of  the  effect  of,  293.  Saw- 
dust with,  293. 

Guns,  steam,  129.  Properties  of, 
132. 

H. 

Hair-springs  of  watches,  193,  204, 
206. 

Halsers,  166. 

Hammers,  tilt,  used  in  iron-works, 
236. 

Hands  of  clocks,  196. 

Hardening  steel,  242. 

Hargreaves,  James,  invention  of 
Iha  spinning-jenny  by,  168. 

Haerlem  rail-way,  321,  334. 

Harness  of  a  loom,  175. 

Harnessing  of  horses,  14,  18,  84. 

Hartz,  depth  of  the  shaft  in  the, 
298. 

Hatchet  experiments  with  alloys, 
215,  note. 

Hats,  manufacture  of,  182. 

Hawk's-bill  in  clocks,  198. 

Heart-wheels,  64.  | 


Heat,  effect  of,  on  pendulums, 192; 
on  glass,  261.  Arts  of  indura- 
tion by,  262. 

Heathcoat's  lace-machine,  178. 

Heaved  veins,  285. 

Heddles  of  a  loom,  175. 

Hemp,  ropes  made  of,  166.  Spin- 
ning, 167.  Machines  for  spin- 
ning, 167.  Paper  made  of,  183. 

Herculaneum,  glass  found  at,  261. 
See  Pompeii. 

Hero's  fountain,  140,  159. 

High-pressure  engines,  nature  of, 
105.  Of  Evans  and  Woolf,  106 
Form  of,  114.  Operation  of, 
114.  Steam-power  applied  to, 
127. 

High-temperatures,  use  of  steam 
at,  126. 

Highs,  Thomas,  168,  note. 

Highways,  19. 

Holland,  canals  in,  36,  302. 

Hollidaysburg  canal,  315,  330 
Railway  from,  to  Johnstown, 
332,  334. 

Home,  Sir  Everard,  on  the  loco 
motion  of  serpents,  11. 

Hooke's  universal  joint,  57. 

Horizontal,  wheels,  95.  Wind 
mills,  100.  Scapements  of  time 
keepers,  193. 

Hornblower,  application  of  expan 
sive  steam  by,  120. 

Horology,  arts  of,  187. 

Horses,  on  attaching,  to  wheels, 
14,  18,  84.  The  power  of,  84; 
compared  with  man's,  84. 
Force  and  speed  of,  84.  The 
drawing  of,  in  circles,  85  ;  on 
revolving  platforms,  85.  On 
American  rail-ways,  328. 

Hosken,  Lieutenant,  commander 
of  the  Great  Western  steam- 
ship, quotation  from  Redfield's 
letter  to,  44,  note. 

Hot  blastjin  smelting  furnaces, 233. 

Hot-pressed  paper,  184. 

Hour-hands  of  clocks,  196. 

Hour-wheel  of  watches,  206. 

Household  pumps,  148. 

Howth.  diving-bell  used  at,  46 


INDEX, 


iSbb 


Hubs  of  wheels,  16. 

Hudson,  dam  across  the,  309. 

Human  power,  82,  84.  Buchan- 
an on,  83.  On  estimatuag  the 
different  applications  of,  S3. 

Hungarian  machines,  157. 

Hydraulic  rams,  160. 

Hydreole,  144. 

Hydrostatic  press,  151. 

I. 

Inclination  of  a  mineral  plane,  280. 

Inclined  plane  wheels,    55,    note. 

Inclined  planes,  canal  boats  moved 
by  means  of,  35,  311. 

Inclined  planes  and  stationary  en- 
gines on  rail-roads,  328,  332. 
Machinery  for  working,  333. 

Inclined  shafts,  in  mining,  297. 

Inclined  wheels,  69. 

Indian  steel, experiments  with,  241. 

Indications  of  metallic  mines,  gen- 
eral observations  on  the  285. 
Negative  and  positive,  288. 
See  Lodes,  Mines,  Ores,  and 
Veins. 

Induration  by  heat,  262. 

Inertia,  an  obstacle  to  locomotion, 
11. 

Inland  navigation  of  the  United 
States,  299. 

Instruments  used  in  subterranean 
operations,  289.  See  Subterra- 
nean. 

Interlaced  masses,  283,  285. 

Inventions,  elementary,  for  the 
cotton  manufacture,  168. 

Iron,  gilding  on,  217.  Plating  on, 
222.  Articles  of,  tinned,  229, 
Valuable  properties  of, 
Extraction  of,  232.  Smelt- 
232.  Crude,  233.  Cast- 
233.  Malleable,  235.  For- 
235.  Rolling,  237.  Slit- 
ting, 237,  238.  Wire-drawing, 
238.  Nail-making  from,  239. 
GuB-making,  239.  Used  for 
coloring  glass,  258.  Places  for 
finding,  286.  Ore,  in  America, 
324. 

Iron-hat, 
II 


230. 
231. 

ing. 
ginS» 


289. 


33 


Iron  pipes,  137. 

Iron  rails,  introduction  of,  318. 

America,  324. 
Italy,  Artesian  wells  in,  275. 


Jamaica  and  Brooklyn  rail-way, 
322,334.  Cost  of  rails  and  chaiVs 
for,  324.    Sleepers  on  the,  324. 

Jenny,  spinning,  168. 

Jessop's  pistons,  122. 

Jewelling  watches,  207. 

Jews,  sun-dials  among  the,  187. 

Johnstown,  rail-way  to,  332,  334. 

Joint,  the  universal,  57.  The  tog- 
gle, 74. 

Juniata  rail-way,  325.  Plan  pro- 
posed for  the  superstructure  of 
the,  326. 

K. 

Keel  of  a  ship,  38. 

Kidderminster  carpets,  177,  178. 
Kilns,    for    burning    bricks,    264 

For  burning  pottery,  269. 
Kingstown   rail-way,   819.      Cost 

of  the,  326. 
Kitspuhl  mine,  depth  of,  298 
Knee,  or  toggle,  joint,  74. 
Knives,  244,  245. 
Kyan's    anti-dry-rot   preparation, 

324. 

L.   ♦ 
Lace-machines,  Heathcoat's,  178 
Laces,  178. 
Lachine  canal,  301. 
La  Garousse,  lever  of,  74. 
Lambert's  wheels,  94. 
Languedoc  canal,  37,  301. 
Lanterns  to  pinions,  54,  56. 
Lap,  cotton  in,  170. 
Lardner,    on   the    power   of   the 

steam  engine,  124. 
Lay  of  a  loom,  175. 
Lead,  pipes  of,  137,  and  137,  note, 

227.     Mineralized   by  sulphur, 

226.    Extraction  of,  226.    Man- 
'    ufacture  of,   227.    Sheet,  227. 

Shot,  228.      Places  for  finding, 

286. 
Leaf,  gold,  216. 

XII. 


386 


INDEX. 


Leather,  used  about  pumps,  1^3. 

Leaves,  of  pinions,  54.  In  hed- 
dles,  175. 

Leeway  of  a  ship,  41. 

Lenticular  masses,  280. 

Leslie,  on  the  force  and  speed  of 
horses,  84. 

Lever,  the  universal,  74.  Of  La 
Garousse,  74. 

Lifting  pumps,  152. 

Lighthouses,  American,  299. 

Line,  of  traction,  or  draught,  14, 
18,  84.     Of  centres,  54. 

Linen  rags,  paper  made  of,  183. 

Linens,  180.  Machines  for  spin- 
ning, 180.  Manufactured  by 
the  Egyptians,  181. 

Live  pulleys,  76. 

Liverpool  and  Manchester  rail- 
way, locomotives  on  the,  80, 
318.  Crossing  of  Chat  IMoss  by 
the,  323.  Cost  of  the,  325.  An- 
nual expenses  of  the,  327. 

Localities  of  ores,  see  Ores. 

Locks,  canal,  34,  303,  308.  Sub- 
stitute for,  35. 

Locomotion,  aids  to,  12. 

Locomotive  engines,  use  of,  on 
rail-roads,  29,  318.  Historical 
facts  respecting,  30.  Premium 
for,  30.  Weight  and  power  of, 
30.  Improvements  in,  31.  In- 
ternal conduction  of,  123.  Op- 
eration of,  124. 

r.odes,  280.  Origin  of,  281.  The 
gangues  in,  282,  285.  Of  four 
species,  283.  The  rake-vein, 
283.  The  pipe-vein,  283,  284. 
Flat,  or  dilated,  vein,  283,  284. 
The  interlaced  mass,  283,  285. 
Accumulated  vein,  284.  Faults, 
or  shifts,  in,  285.  See  Mines 
and  Veins. 

London,  first  paved,  20,  7ioie.  Ar- 
tesian wells  in,  275. 

Longitudinal  galleries,   295,  297. 

Looking-glasses,  silvering  of,  230. 

Looms,  169,  176. 

Low-pressure  engines,  boilers  in, 
108,  109.   Construction  of,  115. 

Low  temperature,  use  of  vapors  of, 
127.      Fluids  boiling  at,  127. 


Lowell  rail-road,  319,  334. 
Lucas,    conversion   by,    of    toola 

of    cast-iron   into    good    steel, 

246. 
Lustre-ware,  272.     Gold  and  sil 

ver,  273. 
Lying  heaps,  280. 
Lyons,  rail-way  near,  318. 
Lysicrates,  choragic  monument  of, 

265. 

M. 

McAdam  roads,  20. 

Machinery,  elements  of,  50.  Ro 
tary,  or  circular  motion  in,  51. 
Distant  rotary  motion  in,  59. 
Change  of  velocity  in,  60.  Al- 
ternate or  reciprocating  motion 
in,  62.  Parallel  motion  in,  65. 
Rack  and  segment  in,  70.  Rack 
and  pinion,  70.  Belt  and  seg- 
ment in,  71.  Scapements  in, 
71.  Continued  rectilinear  mo- 
tion in,  73.  On  engaging  and 
disengaging^  75.  Equalizing  mo- 
tion in,  76.  Friction  in,  79. 
Moving  forces  of,  81.  See  Mov- 
ing Forces. 

Machines,  50.  Remarks  on  sim- 
ple and  complex,  80.  Zurich, 
146.  The  Hungarian,  157.  At- 
mospheric, 159.  For  spinning 
linen,  180.  For  manufacturing 
paper,  184.  For  coining,  220. 
See  Machinery. 

MTaggart,  canal  by,  305. 

Magic  porcelain,  273. 

Magnetic  compass,  used  in  subter- 
ranean operations,  289;  the  dial 
of  it,  289. 

Magnetic  engines,  134. 

Magnetic  iron-ore,  286. 

Maintaining  power  of  time-pieces, 
190. 

Malleability  of  metals,  235,  236 

Malleable  iron,  235. 

IMan,  power  of,  to  produce  motion, 
82.     See  Human. 

Manchester  rail-way,  see  Iiiver 
pool. 

Manganese,  used  for  coloring  glass, 
258. 


INDEX. 


387 


Mangles,  71.  i 

Man-holes  for  steain-angines,  110. 

Maple  sugar,  manufacture  of,  337. 

Marseilles  quilts,  177. 

Masses  of  mineral  deposits,  280. 
The  interlaced,  283,  285. 

Matrix  of  a  metal,  209. 

Medals,  coining,  220.  Of  gun- 
metal,  226,  no^e.  Copying,  349. 

Melting  the  frit  of  glass,  250. 

Melting-pots,  materials  for,  265. 

Menai  bridge,  23,  125. 

Mercurial,  or  disengaging,  process, 
in  photogenic  drawing,  358. 

VIercury,  used  in  silvering,  230, 
231.,  Places  for  finding,  287. 
See  Quicksilver. 

Metallic  baths,  Parkes's,  244. 

Metallic  deposits,  negative  and 
positive  indications  of,  288. 

Metallic  mines,  general  observa- 
tions on  the  indications  of,  285. 
See  Mines  and  Ores. 

Metallic    oxides,  249,  256. 

Metallurgy,  arts  of,  208. 

'Vietals,  extraction  of,  209.  Na- 
tive state  of,  209.  Mineralized, 
or  in  the  state  of  ore,  209. 
Gangue,  or  matrix,  of,  209.  Sor- 
ting, 209.  Stampiag,  209. 
Washing,  209.  Roasting,  210. 
Smelting,  210.  Reducing,  210. 
Refining,  210.  Assaying,  210. 
A-Uoys  in,  211.  Gilding  on, 
216.  AnnerJ.ing,  216,  .note. 
Coining,  219.  Platmg  on,  220. 
Gun,  bell,  and  speculum,  225, 
226.  :>lould3  for  casting,  233. 
Meaning  of  the  word,  as  ap- 
plfed  to  glass,  248,  note,  250. 
Employed  as  coloring  materials 
for  glass,  258.      See  Ores. 

Mexico,  depth  of  a  mine  in,  298. 

Miea-slate,  232. 

Milling  coins,  219. 

Mills,  drawing  in,  by  horses,  85.' 
Barker's,  or  Parent's,  96. 
Wind,  97.  Post,  99.  Hori- 
zontal wind,  100.     Fulling,  181. 

Mineral  veins,  see  Lodes  and  Veins. 

Mineralized  metals,  209 


Mineralizer,  209. 

Miners,  distinction  of  mineral  veins 
by,  283.  Aided  by  geology, 
287.  Means  of,  for  penetrating 
into  the  interior  of  the  earth, 290. 
Shovels  of,  290.     See  Mines. 

Mines,  copper,  222,  286.  Ure's 
Dictionary  on,  279.  Indications 
of  metallic,  285.  Geology  a 
guide  in  the  investigation  of, 
287 — 289.  Instruments  em- 
ployed in,  289.  Tools  used  in, 
290.  Value  and  use  of  gun- 
powder in,  291.  Use  made  of 
fire  in,  294.  Depth  of  several, 
297,  298.  See  Earth,  Excava- 
tion, Lodes,  Miners,  Ores,  and 
Veins. 

'  Mint  in  England,  220. 
Minute-hands  of  clocks,  196. 

;  Minute-wheels  of  watches,  205. 
3Iirrors,  silvering  of,  230. 

\  Mixed  pumps,  151. 

I  Money,  coinage  of,  219. 

I  Montgolfier  invented  balloons,  48. 
^Monument  of  Lysicrates,  265. 

j  Moody,  Paul,  174,  and  l'^4,  note 
Moreys'  engines,  123,  128. 
3Iorris  canal,  311,  315. 
Motion,  51.     Rotary,  or  circular, 

i  51.  Distant  rotary,  59.  Change 
of  velocity  in,    60.     Alternate, 

I      or  reciprocating^2.     Parallel, 

i      65.     Continuedrectilinear,  73. 

i      Change  of  direction  in,  74.     On 

;j      equalizing,  76.     Rotary,  in  Bar- 

'      ker's  mill,  96.     Parallel,  intro- 

i      duced  into  steam-engines,  122. 

\Motion  of  animals,  9,  10. 

I  Moulding  glass,  254. 
Moulds,  paper,  184.     For  casting 

jj      metals,  233.      For  glass,  254, 

||      255.     For  casting  pottery,  269 

'      Saggars,  269. 
Movement,  the  regulating,  of  time- 

;       pieces,  191. 

I  Moving  forces  used  in  the  arts,  81; 
kludge  on  speculum-metal,  226 
Mule°s,  169. 

|:  Mule-spinning,  173. 

ii  Mummies,  glass  found  with,  261 


388 


INDEX. 


Murray's  engine,  116,  123. 
Muscular  power,  82.    Of  men,  82. 

Of  horses,  84. 
Muskets,  manufacture  of,  239. 

N. 

Nail,  a  rod  used  by,  miners,  291. 

Nail-making,  239. 

Nap  of  broadcloths,  182. 

Napoleon,  reward  offered  by,  180. 

National  road,  331. 

Native  state  of  metals,  209. 

Natural  steel,  241. 

Naves  of  wheels,  16,  note. 

Navigation,  steam,  42,  45.  Sub- 
marine, 47.  Inland,  in  Ameri- 
ca, 299,  314.  Slack-water,  306, 
314. 

Needles,  polishing,  246. 

Negative  indications  of  metallic 
deposits,  288. 

Nests,  in  geology,  280. 

Newcastle  rail-way,  320,  335. 

Newcomen's  atmospheric  engine, 
115,  120. 

New  Orleans,  see  New  York. 

NewsUam's  fire-engines,  163. 

New  York,  route  and  distances 
from,  to  New  Orleans,  300. 

New  York  canal,  see  Erie. 

New  York  rail-way,  see  Haerlem 
and  Paterson. 

Niagara  andAiffalo  rail-way,  321, 
334, 

Niokel,  localities  of,  287. 

Nodules,  in  geology,  280. 

Non-condensing  engines,  see  High- 
pressure  engines. 

Noria,  143. 

No.ristown  rail-road,  321. 

O. 

Oars,  propulsion  of  boats  by,  42. 

Obstruction  of  pipes,  139. 

Off-cast  veins,  direction  of,  285. 

Ohio  rail-road,  325,  335. 

Open  trench,  working  by,  in  min- 
ing, 296. 

Open  workings,  in  mining,  296. 

Ores,  209.  Locality  of,  282,  285. 
Value  of  geology  for  finding, 
287.     -See  Mines. 


Overflowing  wells,   see  Artesian. 

Overshot-wheels,  85.  Pressure  of 
the  atmosphere  on,  88.  Most 
advantageous  velocity  of,  90. 

Oxides    metallic,  249,  256. 


Pacos,  289. 

Paddles,  pro^^alsion  of  boats  by, 
42,  43. 

Paddle-wheels,  42. 

Painted  glass,  257.    See  Stained 

Pakfong,  Chinese,  226. 

Pallets,  of  scapements,  72.  In 
clocks,  196.  Gathering,  of  a 
clock,  198,  199. 

Palmer,  rail-way  of,  27.  On 
dust  on  rail-ways,  29. 

Pantheon,  Rotunda  of  the,  brick, 
262. 

Paper,  materials  for,  183.  Man- 
ufacture of,  183.  Sized,  184. 
Blotting,  184.  Hot-pressed, 
184.  ^lachines  for  manufactur- 
ing, 184.  Rapidity  of  manufac- 
turing, 185.  Preparation  of, 
for  photographic  drawing,  365 

Parachutes,  49. 

Parallel  motion,  65,  122. 

Parent's  mill,  96. 

Paris,  first  paved,  20,  note. 

Parkes,  metallic  baths  of,  244. 
On  supplying  the  Chinese  with 
cobalt,  270,  note. 

Parting  gold,  213. 

Party-gold,  216. 

Pascal,  hydrostatic  press  by,  151. 

Passenger-boats,  see  Boats. 

Passenger-cars,  329. 

Passey,  paper  in  the  possession  of, 
185. 

Passings,  in  rail-ways,  28. 

Paste  gems,  258. 

Paternoster-work,  157. 

Paterson  rail-way,  320,  334. 

Patterns,  for  castings,  233. 

Pavements,  19.  Wooden,  20.  In 
ancient  cities,  20,  note.  Tel- 
ford's, 20,  7wte. 

Peace,  Temple  of,  262. 

Pearl  buttons,  brass  eyes  of,  224. 

Pearson,  on  gun-metal,  226,  note. 


[NDEX. 


389 


Pebbles,  use  of,  in  pavements,  20, 

Pendulums  of  clocks,  191,  195. 
Remedies  for  the  effect  of  heat 
on,  192.      See  Hair-springs. 

Penknives,  244,  245. 

Pennsylvania  canal,  315,  328,  330, 
331. 

Pennsylvania  State  canals,  travel- 
ling'on  the,  306. 

Perkins,  propelling  wheel  of,  43. 
On  getting  rid  of  back-water, 
92.  Generators  in  the  engines 
of,  113,  7iote.  Steam-gun  by, 
129.     Inventions  by,  129,  note. 

Perpendicular  pits,  297. 

Perpetual  screws,  57. 

Persia,  ancient  bricks  in,  262, 

Persian  wheels,  143. 

PeterhofF,  fountains  at,  162. 

Phials,  Bologna,  251. 

Philadelphia  rail-way,  see  Colum- 
bia and  Xorristown. 

Photogenic  drawing,  350,  Prepar- 
ing the  plate  for,  351.  Coating 
the  plate  for,  353.  Use  of  the 
camera  obscura  in,  356.  Sea- 
sons for,  357.  3Iercurial,  or  dis- 
engaging, process  in,  358.  Fix- 
ing the  impression  in,  360. 
Talbot's  experiments  in,  362. 
Ponton's  method  of  preparing 
paper  for,  365. 

Photography,  350.  See  Photo- 
genic drawing. 

Pick,  used  by  miners,  290,  296. 

Picker,  cotton,  169. 

Piercers,  of  cartridges,  292. 

Piers,  of  bridges,  22. 

Pig-iron,  2337 

Piles,  in  rail-roads,  322,  323. 

Pinchbeck,  224. 

Pinion,  53.  Leaves  of,  54.  Lan- 
terns to,  54,  56.  Rack  and,  70. 
In  watches,  205.  Cannon,  206. 

Pins,  225, 

Pipe  clay,  267, 

Pipe-veins,  283,  284. 

P'lpes,  steam,  117,  Eduction,  118. 
Water*,  136.  Wooden,  137. 
Iron,  137.  Copper,  137.  Lead, 
137,227.  Stone,  138.  Earthen, 
138.     Friction  of,  138.     Quan- 


tity  of  water  conveyed  in, 
138,  139 .     Velocity  of  water  in , 

138,  Size   and   form  of,   138, 

139.  Curves  in,  to  be  avoided, 
139,140.  Obstruction  of,  1.39. 
Arrangement  of,  156. 

Pistons,  of  steanj-engnies,  117, 
118,  122,  123.  lor  pumps, 
151,  152. 

Pitch  lines,  54. 

Pits,  perpendicular,  297. 

Pivots,  meaning  of,  195,  yioie. 

Planchets  in  coining,  219. 

Planet  wheels,  67, 

Plate  slass,  253. 

Plated^ baskets,  222. 

Plates,  tin,  229,  230,  237. 

Plating  with  silver,  220,  222. 

Plunger  pumps,  149. 

Plyin^g  cotton,  170,  171. 

Po'interolle,  290. 

Polishing,  silver,    219.       Cutlery 
246.     Plate  glass,  254. 

Poll  of  a  pick,  290. 

Pompeii,  pavements  in,  20,  note. 
Glass  found  at,  261. 

Pompey  introduces  the  clepsydra 
into  the  Senate  House,  188. 

Ponton,  3Iungo,  365. 

Porcelain,  Reaumur's,  259.  In- 
gredients of,  265.  Manufacture 
of,  266.  Drawings  on,  270.  Chi 
nese,  271.  Eultpean,  271. 
Earths,  in  the  United  States, 
272.   Gilding,  272.   Magic,  273. 

Portage,  see  Alleghany. 

Portland  vase,  273.    Imitated, 273. 

Positive  indications  of  metallic  de- 
posits, 288. 

Post-mills,  99. 

Potence,  in  a  watch,  203. 

Pottance,  in  a  watch,  200,  203. 

Pottery,  265.  Operations  in,  266 
Glazing,  267,  270.     Throwing, 

268.  Pressing,  269.     Casting, 

269.  Burning,  269.     Printing. 

270.  See  Porcelain. 
Pottsville  rail-road,  325,  335. 
Powder,  see  Gunpowder, 
Power,  sources  of,  81,     Vehicles 

of,  81.  x\nimal,  82.  Water, 
85,     Viind,   97,     Steam,   100 


390 


NDEX 


Of  the  steam-engine,  124.  Of 
gunpowder,  130.  The  main- 
taining,  of     time-pieces,    190. 

Power-looms,  169,  176. 

Powers  acting  within  a  boat,  42. 

Precious  stones,  in  watches,  207. 

Press,  hydrostatic,  151. 

Pressed  bricks,  263. 

Pressingof  glass,  255.  Of  pottery, 
269. 

Primary  rocks,  279. 

Primitive,  radius,  54.  Circum- 
ferences, 54. 

Prince's  metal,  224. 

Printing  ware,  270. 

Projecting  water,  161. 

Prongs  of  forks,  245. 

Propelling  power,  on  rail-ways,  29. 

Propelling  wheel   of  Perkins,  43. 

Proportional  radius,  54,  7iote. 

Providence  rail-way,  321,  334. 

Proximate  positive  indications  of 
metallic  deposits,  288. 

Puddle  for  lining  canals,  33 

Puddling-furuaces,  235. 

Pulleys,  76. 

Pulp  for  paper,  184,  185. 

Pumps,  in  steam-engines,  118. 
Rope,  143.  Spiral,  145.  Cen- 
trifugal, 146  Common,  147. 
Household,  or  sucking,  148. 
Forcing,  149.  Plunger,  149. 
De  la  Hi«s,  151.  Mixed,  151. 
Lifting,  152,  Bag,  153.  Dou- 
ble-acting, 153.  Rolling,  154. 
Eccentric,  155.  Chain,  157. 
Bead, 157.  Cellular,  157. 

Punt,  or  punting-iron,  251,  note. 

Puppet  valves,  121. 

l*yramids,  125,  263,  note. 


Uuadrupeds,  locomotion  of,  10. 
Swimming  of,  11. 

Quartation  of  gold,  214. 

Ciuarter,  wind  upon  the,  39. 

Q,uicksilver,  alloys  of,  211.  Ex- 
traction of  gold  by  amalgama- 
tion with,  212.      See  Mercury. 

Quilts,  Marseilles,  177. 

Quincy  rail-way,  318,  334. 


R 

Rack,  and  segment,  70.  And  pin 
ion,  70.  Of  a  wheel  in  clocks, 
198,  199. 

Racks,  73. 

Radius,  54,  and  54,  note. 

Rag  wheels,  52. 

Rags  for  making  paper,  183. 

Rails,  materials  of,  25.  Weigh* 
of,  27.  Introduction  of  cast- 
iron,  318  ;  of  malleable  iron, 
318.   In  the  United  States,  324. 

Rail-ways,  object  of,  24.  Modern, 
24.  Compared  with  turnpikes, 
and  canals,  24.  On  the  con- 
struction of,  24,  323.  The  dif- 
ferent varieties  of,  25.  Pas- 
sings, or  sidings,  in,  28.  Turn- 
plates  in,  28.  Curves  in,  28. 
Crossing  public  roads,  29.  Dirt 
on,  29.  Propelling  power  on, 
29.  Locomotives  for,  29.  Sta- 
tionary engines,  and  inclined 
planes  on,  31,  328,  332.  Am- 
erican, 298,  299,  318,  334. 
Foreign,  318.  The  sleepers 
in,  324.  Cost  of  American. 
325,  326  ;  of  English,  32.5 
Annual  expenses  of,  327,  329 
Horses  on,  328.  Fuel,  328. 
Grubbing,  331.  Machinery  for 
working  inclined  planes  on,  333. 
Tables  of,  in  the  United  States, 
334—336. 

Raising  water,  142.     See  Water. 

Rake-veins,  283, 

Rams,  hydraulic,  160, 

Rasping  beets  for  sugar,  341. 

Ratchet  wheels,  58. 

Razors,  244,  245. 

Reaumur,  porcelain  of,  259,  On 
glass  thread,  260. 

Receivers,  in  pressing  glass,  255. 

Reciprocating  motion,  62. 

Rectilinear  motion,  continued,  73. 

Redfield,  W.  S.,  44,  7iote. 

Reduction  of  metals,  210, 

Refining  metal,  210, 

Regulating  movement  of  time- 
pieces, 191 

Regulator  of  a  watch,  193 


INDEX. 


391 


Remote  positive  indications  of  me- 
tallic deposits,  288. 

Rents,  in  geological  strata,  281. 

Reservoirs  for  beet  juice,  342. 

Retarding  wheels,  31. 

Rideau  canal,  305,  307. 

Roads,  hints  on,  19.  Me  Adam, 
20.  Loss  of  power  on,  24. 
The  National,  331 

Roasting  ores,  210. 

Robinson,  Moncure,  on  the  cost 
of  rail-ways,  325.      Cited,  326. 

Robison,  John,  on  the  overshot 
wheel,  86.  On  the  escape  of 
air  and  water  through  a  hole,  88. 
Describes  a  machine,  89. 

Rocket  engines,  30. 

Rocks,  134.     See  Blasting. 

Rollers,  13. 

Rolling  and  slitting  iron,  237. 

Rolling  pumps,  154. 

Roman  coins,  226,  note. 

Romans,  aqueducts  among  the, 
136.   Windows  among  the,  261. 

Rome,  paved,  20,  note.  The  first 
sun-dial  at,  188;,  The  clepsy- 
dra brought  to,  188,  note. 
Ancient  bricks  at,  262. 

Roofs,  covered  with  tiles,  264. 

Rope-^umps,  143. 

Ropes,  165. 

Rotary, or  circular,motion,51.  Dis- 
•tant,  59.     In  Barker's  mill,  96. 

Rotary  valves,  121. 

Rotative  engines,  126. 

Rotunda  of  the  Pantheon,  262. 

Rouge  d'  Angleterre,  246. 

Routes  of  canals  and  rail-roads  in 
North  America,  300,  314,  334. 

Roving-frames,  170,  171.  Sim- 
pler form  of,  172, 

Ilovvutree's  engines,  163. 

Roy,  on  expansion  of  glass,  261. 

Rubies,  in  watches,  207. 

Rudder  of  a  ship,  38. 

Rupert's  drops,  251. 

Russel,  on  the  velocity  of  wave  in 
canals,  302. 

Russia,  fountains  in,  162. 

S. 
Safety  gates  in  canals,  34. 


Safety-valves,  112. 
Saggars,  269. 

Before  the  wind,  39 


Sailing,  37. 


Sails  of  windmills,  97.  Angle  for, 
98.     Adjustment  of,  98. 

St.  Austle,  steam-engine  at,  125. 

Sampson  mine,  shaft  at  the,  298. 

Sand,formoulds,233.  Inglas3,24S. 

Sankey  Brook  canal,  301. 

Santee  canal,  301,  317. 

Saratoga  and  Schenectady  rail 
way,  320,  334.  Cost  of  the,325. 

Sarcophagi,  glass  found  on,  261. 

Savannah,  steam-ship,  44. 

Sawdust,  with  gunpowder,  293. 

Saws,  244,  245. 

Saxony,  the  porcelain  of,  272. 

Scapements,  71.  Pallets  of,  72 
Crutch,  72.  Watch,  72.  Of 
time-pieces,  193,  200,  204. 

Scape-wheels,  193,  204. 

Schemnitz  vessels,  157. 

Schenectady,  see  Albany,  Sarato 
ga,  and  Utica. 

Schists,  gold  found  in,  286. 

Schuylkill,  bridge,  22.  Slackwatei 
navigation,  306,  316. 

Scissors,  244,  245. 

Scoop  wheels,  142. 

Scoria,  232. 

Scotland,  canal  in,  36. 

Screws,  propulsion  ^f  boats  by,  42 
Perpetual,  or  endless,  57.  De- 
finition of,  74.  Archimedes' 
144.     The  water,  145. 

Scudding  before  the  wind,  39. 

Secondary  rocks,  279. 

Segment,rack  and.70  Beltand,71. 

Semicircle,  used  by  miners,  289. 

Separating  metal,  209. 

Serpents,  locomotion  of,  11. 

Setting  the  edges  of  cutlery,  246. 

Severus,  Alexander,  Portland  vase 
discovered  in  the  tomb  of,  273. 

Sevres,  porcelain  made  at,  271. 

Sewing-thread  spun  by  mules, 174. 

Shafts,  to  ventilate  canal  tunnels, 
33.  Means  of,  195,  note.  In 
mining,  295.     Depths  of,  297. 

Shanks  of  brass  buttons,  224 

Shearing  cloths,  182- 


392 


INDEX. 


Shear-steel,  241. 

Sheet  lead,  227. 

Sheldrake,  T.,  inclit'.ed  plane 
wheels  by,  55,  note. 

Shifts,  in  mineral  veins,  285. 

Ships,  form  of,  37.  Bows  of,  38. 
Keels  and  rudders  of,  38.  Ef- 
fects of  wind  on,  39.  Stability 
of,  41.  Crank,  41.  ToostifF,41. 

Shooting  tools  of  miners,  290. 

Shot,  manufacture  of  leaden,  228. 

Shovels,  miners,'  290. 

Shrouds,  166. 

Shuttles,  175. 

Sidings,  in  rail-ways,  28. 

Silesia,  use  of  sawdust  in,  293. 

Silver,  extraction  of,  217.  Eliqua- 
tion  of,  218.  Working,  218. 
Solder  used  for,  219.  Polishing, 
219.     Alloyed,  219.     Coining, 

219.  Milling,  219.  Plating  with, 

220,  222.  Edges,  221.  Ger- 
man, 226.  Use  of,  for  coloring 
glass,  258.     Localities  of,  286. 

Silvering  of  mirrors, 230.  Of  look- 
ing glasses,  230.  Of  glass 
globes,  231. 

Silver-lustre  ware,  273. 

Silversmiths'  work,  218. 

Simplon  and  Mount  Cenis,  298. 

Singing  cotton  fabrics,  ISO. 

Single  rail-wav'S,  27. 

Size,  of  wheels,  13.  Of  canals,  36. 

Sizing  paper,  184. 

Slackwater  navigation,  306,  307. 
In  canals,  307,  314,  330. 

Slag,  232. 

Sleepers,  used  on  rail-roads,  324. 

Sliding  valves,  121. 

Slip,  used  in  pottery,  269. 

Slitting  iron,  237,  238. 

Sliver,  cotton  in,  170. 

Slubbing  machine,  181. 

Smeaton,  on  muscular  power,  84. 
On  the  velocity  of  wheels,  90, 
91.     On  float-boards,  91. 

Smelting,  metal,  210.    Iron,   232. 

Smifts,  used  in  blasting,  290,  291. 

Snails,  water,  144.  In  clocks,  198. 

Snifting-valves,  118. 

Solder,  for  silver,  219.  In  pla- 
ting copper,  221. 


Sorting  metal,  209. 

Sources  of  power,  81.    See  Power 

Sparry  iron-ore,  241. 

Speculum-metal,   225,    226,  230. 

Speed,  of  steam-boats,  44,  and 
44,    note.     See  Velocity. 

Spencer,  on  voltaic  electrical  en- 
graving, 348—350. 

Spindle-rails,  171. 

Spinning,  mechanism  of  simple, 
165,  168.  Hemp,  167.  Cotton, 
172.     Mule,  173.      Glass,  260. 

Spinning-frames,  168,  173. 

Spinning-jenny,  168. 

Spiral  gear,  55,  and  55,  note.  . 

Spiral  pumps,  145. 

Spiral  wheels  and  water-screws, 
propulsion  of  boats  by,  42. 

Spoon,  of  the  Zurich  machine,  146. 

Spouting  wells,  see  Artesian  wells. 

Springs,  of  carriages,  17.  Of 
watches,  190,191,200,201,204. 

Spur-gearing,  53. 

Stability  of  a  ship,  41. 

Staffordshire,  mine  in,  298. 

Stained   glass,   256,  258. 

Stamping  metal,  209. 

Started  veins,  285. 

State  works,  300. 

Stationary  engines.     See  Inclined. 

Steam,  propulsion  of  vessels  by, 
42.  Expansion  of  water,  when 
converted  into,  100.  Atnws- 
pheric  weight  upon,  101,  102, 
Increase  of,  after  separation 
from  water,  101.  Three  meth- 
ods of  obtaining  power  from, 
103.  Application  of,  to  engines, 
114.  Use  of,  at  high  tempera- 
tures, 126  ;  at  low  tempera- 
tures, 127.  Substitution  of,  for 
gunpowder,  129. 

Steam-boats,   42.     Speed  of,  44. 

Steam-carriages,  129. 

Steam-engines,  42.  Cartwright's, 
67,122.  Governors  in,  76,  110, 
117.  Estimation  of  the  power 
of,  by  horses' power,  84.  Ear- 
liest attempts  at  forming,  103. 
Remarks  on,  107.  Boilers  in, 
108.  Appendages  to,  110 
Brathwaite  and  Ericsson's,  113 


INDEX. 


S93 


Application  of  steam  to,  114. 
Newcomen's  atmospheric,  115, 

120.  Description  of  the  double- 
acting,  116.  Expansion,  119. 
Condensers  in,  120.     Valves  of, 

121.  Pistons,  122.  Parallel 
motion  in,  122.  Estimates  on 
the  power  of,  124.  At  St. 
Austle,  in  Cornwall,  125.  Pro- 
jected improvements  in,  126. 
Rotative,  126.  See  High-pres- 
sure, Inclined  plants.  Locomo- 
tive, and  Low-pressure. 

Steam-guages,  110. 

Steam-guns,  129. 

Steam-navigation,  42,  45. 

Steam-pipes,  117. 

Steam-power,  100. 

Steam-ships,  the  Atlantic  first  cros- 
sed by,  44.  The  Great  Wes- 
tern, 44,  note,  45.  The  Brit- 
ish Queen,  45. 

Steel,  gilding  on,  217.  Hardness 
and  tenacity  of,  232.  Iron  re- 
combined  with  carbon,  240. 
The  iron  used  in,  240,  241.  Ce- 
mentation of,  240.  Blistered, 
240.  Tilted,  240.  Shear,  241. 
Cast,  241.  Natural,  241.  Al- 
loys of,  241.  Stodart's  and 
Faraday's  experiments  on,  241. 
Indian,  241.  Quantity  of  car- 
bon in,  241,  note.  Case-har- 
dening, 242.  Tempering,  242. 
Cutlery,  245.  Conversion  of 
cast-iron  into,  246. 

Steps,  in  mining  galleries,  296. 

Stevenson,  G.,  rocket-engine  by, 
30.  On  canals  in  North  Ameri- 
ca, 298.     On  rail-ways,  318. 

Stodart,  on  steel,  241. 

Stoddart,  on  gilding,  217,  note. 

Stone,  bridges,  22.    Pipes,  138. 

Stones,  factitious,  employed  by 
the  ancients,  263.  Rail-ways 
laid  on,  319,  321,  323. 

Stone-ware,  manufacture  of,  267. 

Stop-gates,  in  canals,  34. 

Stourbridge  clay,  crucibles  of,  265. 

Strainers,  for  water  pipes,  139. 

Strand  of  a  rope,  166. 


Stratiform  deposits,  279. 

Strength  of  man,  84,  150. 

Stretching,  the  process  of,  173. 

Strikes,  used  in  manufacturing 
sheet-lead,  227. 

Striking  part  of  a  clock,  194,  197. 

Submarine  navigation,  47. 

Subteri-anean  operations,  instru- 
ments for,  289.  Wjrkings,  in 
mining,  296,  297.     $ee  Mines. 

Sucking-pumps,  148. 

Sugar,  maple,  337.     See  Beet. 

Sulphate  of  soda  may  be  employed 
in  glass-making,  249. 

Sulphur,  lead  mineralized  by,  226. 

Sun  and  planet  wheels,  67. 

Sun-dials,  187. 

Superstructure  for  rail-roads,  326 

Supporters  of  rail-ways,  319,  323. 

Suspension  bridges,  23. 

Swab-sticks  of  borers,  290. 

Sweden,  copper  mines  in,  222. 

Swimming,  of  fishes,  10.  Of  land 
animals,  11.     Of  birds,  11. 

Swimming  bladders,  11,  note. 

Switch,  in  rail-roads,  28. 

Swords,  tempering  of,  244,  note. 

Syphons,  141. 

T. 

Table,    of  canals   in   the   United 

States,  314  ;  of  rail-ways,  334. 
Table-forks,  244,  245.   Prongs  of, 

245.      ^. 
Table-knives,  244,  245. 
Tail-water,  remedies  for,  92,  93. 
Talbot,  experiments  by,  362. 
Tamping,  by  miners,  291. 
Tamping-bars,  291. 
Tapestry,  179. 

Taunton  spindle,  see  Danforth's. 
Taylor,  on  depths  of  mines,  297. 
Teazles,  182. 
Teeth  of  wheels,   53.     The  cut 

of,  55,  56. 
Telescopes,  speculum-metal  used 

in,  225,  226,  230. 
Telford,  paved  road  by,  20,  note. 
Temperatures,    use    of    steam    at 

high,  126;  of  vapors  of  low, 127. 
Tempering  steel,  242.  By  metallio 


39'1 


INDEX. 


baths,  244.      By  Ferrara,  244, 

note. 
Temple  of  Peace,  262. 
Tenders,  see  Locomotive. 
Terra-cotta,  264. 
Terre-cuite,  264. 
Test-bars,  240. 

Thames,  bridges  across  the",  22. 
Thenard,  on  steel,  242. 
Theory  of  twisting  flexible  fibres, 

164. 
Thermae,  of  brick,  262. 
Third  wheel  of  a  watch,  203. 
Thread,  gold,  217.     Glass,  260. 
Throttle-valves,  121. 
Throwing,  in  pottery,  268. 
Throwiug-wheels,  163. 
Tides,  velocity  of,  44,  note. 
Tightening  wheels,  76. 
Tiles,  264. 
Tilt-hammers,  236. 
Tilted-steel,  240. 
Timepieces,  189.     Essential  parts 

of,  190.    Maintaining  power  of, 

190.  Regulating  movement  of, 

191.  Pendulums  of,  191.  Bal- 
ances of,  192.  Scapemeuts  of, 
193,  200,  204.  See  Clocks  and 
Watches. 

Tin,  in  bronze,  225.  Extraction 
of,  229.  Block,  229.  Foil,  229. 
Plates,  229,237.  Silvering  with, 
230,  231.-   Localities  of,  285. 

Tin-foil,  229. 

Tinning,  copper,  223.  Plates, 
229,  230. 

Tinstone,  229. 

Toggle  joint,  74. 

Tombac,  224. 

Toothed  wheels,  53. 

Torpedo,  Fulton's,  48. 

Tower  of  the  Winds,  188. 

Traction,  line  of,  14,  18,  84. 

Train  of  a  watch,  202. 

Tram-roads,  27,  318. 

Transition  rocks,  279,  283. 

Transit^  on  rail-ways,  328. 

Transverse  galleries,  295,  297. 

Trautwine,  sections  of  rail  by,  26. 

Travelling,  on  canals,  306. 

Tread  well,  on   using   steam,   113. 


Condensers  by,  121.    Machines 

by,  for  spinning  hemp,  167. 
Tredgold,  24,  43. 
Trench,  working  by  an  open,  in 

mining,  296. 
True  radii,  54. 
Trundles,  in  machinery,  54. 
Tub-wheels,  95. 
Tunnels,  for  rail-roads,  25.     For 

canals,  33.     At  Worsley,  34. 
Turkey  carpets,  179. 
Turnpikes  jnd  rail-roads,  24 
Turn-plates,  on  rail-ways,  28 
Turn-tables,  on  rail-ways,  28. 
Tweeled-cloth,  176. 
Twilled  fabrics,  176. 
Twilling,  176. 
Twisting,  theory  of,  164. 

U. 

Undershot  wheels,  85,  90.  Ve- 
locity of,  91.  Size  of,  91. 
Float-boards  of,  91. 

Universal,  joint,  57.     Lever,  74. 

Utica  and  Schenectady  rail-road, 
327,  334. 


Valenciana  mine,  depth  of,  298. 
Valves,   in  canal-gates,   35.     Of 

steam-engines,   112,   117,   118. 

Different  kinds  of,  121. 
Vapors  of  low  temperature,  127. 
Vases,  273. 
Vehicles  of  power,  81. 
Veins,   282.     Rake,  283.     Pipe, 

283,284.    Flat,  or  dilated,  283, 

284.  The  interlaced  mass,  283, 

285.  Shifts,  or  faults,  in,  285. 
Direction  of  offcast,  285. 
Heaved,  285.  Started,  235. 
Exploring,  296.  See  Lodes 
and  Mines. 

Velocity,  change  of,  in  machinery, 
60.  Of  overshot-wheels,  90. 
Of  undershot-wheels,  91.  Of 
water  in  pipes,  138.  In  cotton 
machines,  170. 

Velvets,  179. 

Venetian  carpets,  178. 

Ventilation  of  tunnels,  33. 


INDEX. 


395 


Verge  of  a   balance-wheel,    203, 

207. 
Vertical  windmills,  97. 
Vessels,  Schemnitz,  157. 
Viaducts,  25,  332. 
Vitrification,  arts  of,  247. 
Voltaic  electrical  engraving,  348. 

W. 

Wagons,  12.    Retarding,  31,  noie. 

Wales,  bridge  in,  23,  125. 

Walking,  10. 

Ware,  Biddery,  229.  Wedge- 
wood's,  265,  267.  Earthen, 
265,  266.  Common  crockery, 
265.  Glazing,  267,  270.  Stone, 
267.  White,  267.  Throw- 
ing, 268.  Pressing,  269.  Cast- 
ing, 269.  Burning,  269.  Print- 
ing, 270.  China,  271.  See 
Porcelain. 

Warning-piece,  in  clocks,  198. 

Warp,  175. 

Warping  cotton,  174. 

Warping-machines,  Moody's,  174. 

Washing  metal,  209. 

Washington,  see  Baltimore. 

Watch  scapements,  72. 

Watches,  fusees  of,  62,  191,  200 
— 202.  Essential  parts  of,  190. 
Maintaining  power  of,  190. 
Springs  of,  190,  191,  200,  201 
—204.  Chains  of,  190,  191, 
200,201.  Barrebin,  191,  195, 
197,  200,  201.  Regulating 
movement  of,  191,  206.  Bal- 
ances of,  191, 192,  203.  Hair- 
springs of,  198,  204,  206.  Reg- 
ulators of,  193.  Scapements  of, 
193,  200.  Description  of,  200. 
Wheel-work  of,  200,  203. 
Guard-gut  of,  202.  Train  of, 
202.  Minute  wheel  in,  205. 
Hour-wheel  of,  206.  Cannon- 
pinion  in,  206.  Curb  in,  206. 
Addition  of  jewels  to,  207. 
Number  of  pieces  in,  208. 
Number  of  trades  employed  in, 
208. 

Water,  movrnient  of  bodies 
through,  3T.     Dead,  37.     Va- 


riations in  the  fall  of,  88.  Great- 
est effect  of  the  action  of,  on 
machinery,  91.  Delivering,  on 
an  undershot-wheel,  ft2,  94. 
Back,  or  tail,  92.  On  breast- 
wheels,  94.  On  horizontal  oi 
«tub-wheels,  95.  In  Barker's, 
or  Parent's,  mills,  96.  Expan- 
sion of,  when  converted  into 
steam,  100.  For  boilers  of 
steam-engines,  108.  Arts  of 
conveying,  135.  Subterranean 
passages  for,  136.  Pipes  for 
transmitting,  136  Velocity  of, 
in  pipes,  138.  Obstruction  of, 
in  pipes,  139.  Conveyed  in  sy- 
phons, 141.  Raising,  142  ;  by 
the  scoop-wheel,  142  ;  by  the 
Persian  wheel,  143  ;  by  the 
noria,  143  ;  by  the  rope-pump, 
143  ;  by  hydreole,  144  ;  by 
Archimedes'  screw,  144  ;  by 
the  spiral  pump,  145  ;  by  t!ic 
centrifugal  pump,  146  ;  Lv 
common  pumps,  147  5  by  the 
forcing  pump,  149  ;  by  the 
plunger  pump,  149  ;  by  De  La 
Hire's  pump,  151  ;  by  the  hy- 
drostatic press,  151  ;  by  the 
lifting  pump,  152  ;  by  the  bag- 
pump,  153  ;  by  the  double-act- 
ing pump,  153  ;  by  the  rolling 
pump,  154  ;  by  the  eccentric 
pump,  155.  Arrangement  of 
pipes  for  raising,  156.  Raising 
by  the  chain-pump,  157  ;  by 
Schemnitz  vessels,  or  the  Hun- 
garian machine,  157  ;  by  He- 
ro's fountain,  159  ;  by  atmos- 
pheric machines,  159  ;  by  the 
hydraulic  ram,  160.  Project- 
ing, 161  ;  by  fountains,  161  ; 
by  fire-engines,  162.  Lifted 
and  projected  by  throwing 
wheels,  163.  Rise  of,  in  Arte- 
sian wells,  276. 

Water-clocks,  189. 

Water-pipes,  136.     See  Pipes. 

Water-power,  85. 

Water-screws,  42,  145. 

Water-snails,  144. 


396 


INDEX. 


Water  spinning-frame,  168. 

Water-wheels,  governors  in,  77. 

Watt,  James,  inventor  of  the  sun 
and  planet  wheel,  67.  On  a 
horse's  power,  84.  Form  of 
boilers  used  by,  107.  Conden- 
ser invented  by,  116,  120. 
Double-acting  engine  of,  116. 
Parallel  motion  introduced  into 
engines  by,  122.  Coining  ma- 
chinery by,  220. 

Weaving,  l''o.  Double,  177. 
Cross,  177. 

Wedgewood,  ware  of,  265,  267. 
Manufactory  of,  267.  Imitated 
the  Portland  vase,  273. 

Weft  of  cloth,  175. 

Weight,  animals  draw  through  the 
medium  of,  15.  Of  rails  for 
rail-ways,  27.  Of  locomotives, 
30. 

Weights,  raising  of,  by  human 
power,  84  ;  by  horse's  power, 
84.     Of  clocks,  190,  195. 

Weirs,  in  canals,  34. 

Wells,  Artesian,  275. 

Wheel-carriages,  12. 

Wheel-work,  of  a  clock,  194.  Of 
a  watch,  200,  203. 

Wheels,  mechanical  action  of,  12. 
Size  of,  13.  Attaching  horses 
to,  14,  18,84.  Broad,  15.  Form 
of,  16.  Cut  of,  17.  Perkins's 
propelling,  43.  Band,  in  ma- 
chinery, 51.  Rag,  52.  Toothed, 
53.  Spiral  gear,  55.  Bevel 
gear,  56.  Crown,  or  contrate, 
56.  Universal  joir.i  instead  of, 
67.  Perpetual  screw,  57.  Brush, 
58.  Ratchet,  58.  Change  of 
velocity  in,  60.  Fusee,  62,  191, 
200 — 202.  Eccentric,  63.  Cams 
for,  63.  Heart,  64.  Cranks  in, 
65.  Sun  and  planet,  67.  In- 
clined, 69.  Epicycloidal,  69. 
Rack  and  segment,  70.  Rack 
and  pinion,  70.  Thrown  into,  and 
out  of,  gear,  76.  Tightening,  76. 
Fly,  78.    Horses  on,  85.    Over- 


shot, 85.  Breast,  85,  94.  Un- 
dershot, 85,  90.  Chain,  88. 
Besant's,  93.  Lambert's,  94. 
Horizontal,  or  tub,  95.  Scoop, 
142.  Persian,  143.  Throwing, 
flash,  or  fen,  163.  Of  clocks, 
194.  Of  watches,  200—206. 
For  making  ware,  266,  268. 

White,  inventor  of  the  spiral  gear, 
55,  note. 

White-metal  buttons,  224. 

White  ware,  manufacture  of,  267. 

Wind,  effect  of  the,  on  ships,  39. 
Action  of,  on  wind-mills,  97. 

Windage,  in  guns,  132. 

Windmills,  vertical,  77.  Hori- 
zontal, 100. 

Windows,  261. 

Wind-power,  97. 

Winds,  Tower  of  the,  188. 

Wipers,  64,    Curves  for,  64, 7iole 

Wire,  gilt,  or  gold,  217. 

Wire-drawing,  238. 

Wirtz,  Andrew,  machine  by,  146. 

Wooden,  pavements,  20.  Bridges, 
21.      Pipes,  137. 

Woof,  of  cloth,  175. 

Wool,  remarks  on,  181. 

Woolf,  engines  of,  103,  106,  120. 

Woolf's  shaft,  depth  of,  298. 

Woollens,  181. 

Wootz,  241. 

Worcester  rail- way,  327,  334. 

Working,  of  gold,  215.  Of  silver 
218.     Of  copper,  223. 

Worm,  the,  57. 

Worsley,  tunnel  at,  34. 

Worsted,  181. 

Wrought-iron,  235. 

Wrought-nails,  239. 

Y. 

Young,  Dr.,  spiral  pump,  used  by, 
146.  On  the  greatest  effect 
produced  by  a  laborer,  150. 

Z. 

Zinc,  223,  287. 
Zurich  machine,  146. 


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